ARTICLE IN PRESS

0044-5231/$ - se

doi:10.1016/j.jc

�Correspondfax: +39098449

E-mail addr

Zoologischer Anzeiger 247 (2008) 209–221

www.elsevier.de/jcz

Ultrastructure of the antennal sensorial appendage of larvae of Ophonusardosiacus (Lutshnik, 1922) (Coleoptera, Carabidae) and possible

correlations between size and shape and the larval feeding habits

A. Giglioa,�, P. Brandmayra, E.A. Ferrerob, P.G. Giulianinib, E. Perrottaa,F.F. Talaricoa, T. Zetto Brandmayra

aDipartimento di Ecologia, Universita della Calabria, I- 87036 Arcavacata di Rende (Cs), ItaliabDipartimento di Biologia, Universita di Trieste, via Giorgieri 7, I-34127 Trieste, Italia

Received 26 June 2007; received in revised form 28 November 2007; accepted 3 December 2007Corresponding Editor: M. Schmitt

Abstract

The antennal sensory appendage morphology was studied in 19 species of carabid beetle larvae using scanningelectron microscopy. Shape and size of the organ has been re-examined in selected taxa and are compared to figure outpossible correlations between antennal sensory structures and larval morphoecological types. Morphometric analysisshows no correlation between antennal sensory appendage dimension and the four most common behavioural types.The ultrastructure of this sensory organ is described for larvae of Ophonus ardosiacus and the possible function isdiscussed. Olfactory function has been indicated as the most probable. The high number of chemosensory neurons ofthis multiporous organ suggests a possible ability of fine odour discrimination related to prey choice or host location.r 2008 Elsevier GmbH. All rights reserved.

Keywords: Larval ground beetles; Olfactory chemoreceptor; Antennal sensory organ; Hyaline vesicle; Larval life styles

1. Introduction

Carabid beetles are a family of Coleoptera widelyspread in all terrestrial habitat where they are importantpredators. Previous studies have been suggested thatthere are correlations between body form and habit (e.g.feeding, locomotory, burrowing, flying) in Carabidbeetle adults (Forsythe 1991; Evans 1994). In carabidlarvae, it is well known that some larval features(mandible form, general body form, urogomphi mor-phology and feeding behaviour) are correlated with the

e front matter r 2008 Elsevier GmbH. All rights reserved.

z.2007.12.001

ing author. Tel.: +390984492982;

2981.

ess: anita.giglio@unical.it (A. Giglio).

main selective pressures of the habitat. Zetto Brandmayret al. (1998) have correlated morphological features,behavioural traits and possible selective pressures bygrouping known species into nine main behaviouraltypes (1. soil pore explorers, 2. surface runners, 3.surface walkers, 4. sand diggers, 5. seed feeders, 6.burrow trappers, 7. C-shape Harpalines, 8. parasitoidsand predatory symbionts, 9. trichome disc larvae).However, very fragmentary information concerns sen-sory equipment of head appendages of larval stagesrelated to the behaviour, feeding habits and use of space.At present, knowledge about larval sensorial equipmentand its possible function regards the rostral processes ofNotiophilus biguttatus (Fabricius, 1779) (Altner andBauer 1982), the adhesive mouthparts of Loricera

ARTICLE IN PRESSA. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221210

pilicornis (Fabricius, 1775) (Bauer and Kredler 1988),the highly modified antennae in Siagona europaea

(Dejean, 1826) (Zetto Brandmayr et al. 2007), themaxillary palps in Nebria (Latreille, 1802) (Spenceand Sutcliffe 1982), the general sensory equipment ofthe ant’s brood-eater larva of Graphipterus serrator

(Forsk(al, 1775) (Zetto Brandmayr et al. 1993) andPaussini larvae (Luna de Carvalho 1991; Bousquet 1986;Di Giulio et al. 2003). Recently, labial and maxillarypalps of 22 larval species belonging to six of the nineproposed behavioural types have been described com-paratively (Giglio et al. 2003). Little informations occuron antennal sensory structure. As in Adephagan larvae,carabid beetles antennae are four-segmented with asensory appendage on the third article, whose form andsize show an interesting variation among species and/orhigher taxa.

The present work is a morphometric comparativestudy of this antennal organ in larvae of some European

Table 1. List of carabid species whose larvae were studied

Behavioural

types

Tribe Genus Species

Surface walkers Carabini Carabus lefebvrei (D

Surface runners Nebriini Leistus *fulvibarbis

Nebria kratteri (D

*germari (H

*dahli (Stu

Notiophilini Notiophilus *rufipes (C

Surface walkers Licinini Licinus silphoides (

Soil pore

explorers

Trechini Trechus *quadristria

1781)

Typhlotrechus *bilimeki (S

Pterostichini Laemostenus

(Antisphodrus)

*obtusus (C

Calathus *glabricolli

*fuscipes (G

*mollis (Ma

*erratus (S

Poecilus cupreus (Li

Seed feeders Harpalini Ophonus *ardosiacus

*sabulicola

Harpalus

(Pseudophonus)

rufipes (De

Harpalus

(Harpalus)

*tardus (Pa

An asterisk (*) marks the specimens preserved in our collection.

species of Carabidae in relation to their morphoecologi-cal type. In addition, in order to assess its functional role,ultrastructural analysis of the antennal sensory appen-dage is provided for Ophonus ardosiacus (Lutshnik, 1922)larvae.

2. Materials and methods

We examined 19 species of 13 genera belonging toseven tribes and four behavioural types (Table 1). Theywere chosen to cover a wide range of taxonomic unitsand to include species with different life history andfeeding preferences. Most samples were collected in thefield and preserved in 70% ethanol (Zetto Brandmayrcollection, Department of Ecology, University ofCalabria); only O. ardosiacus and C. lefebvrei larvaewere obtained ‘‘ex ovipositione’’ in laboratory and

Capture site Larval

stages

ejean, 1826) Lab-rearing spring 2006 III

(Dejean, 1826) Trionto (CS) 22.01.95 III

ejean, 1831) Serra San Bruno (VV) 22.12.97 I/III

eer, 1837) Dolomiti 29.06.80 III

rm, 1815) Slovenia, Slavnik Mount

26.11.74

III

urtis, 1829) Trionto (CS) 14.06.94 III

Rossi, 1790) Trionto (CS) 19.05.93 III

tus (Schrank, Friuli, pastures (Magredi)

21.04.79

II

turm, 1847) Grotta delle Torri (TS)

04.07.83

III

haudoir, 1861) Alpi Liguri 17.09.64 I/III

s (Dejean, 1828) Stena Mount, Carso Triestino

15.12.77

II

oeze, 1777) Sicilia, Nebrodi Mounts

25.04.81

I

rsham, 1802) Sicilia, Peloritani Mounts

30.05.82

III

ahlberg, 1827) Friuli, pastures (Magredi)

25.10.78

II/III

nne, 1758) Tarsia (CS), 14.06.00 I

(Lutshnik, 1922) Lab-rearing 76-77 I/III

(Panzer, 1796) Paolo Mounts Faenza,

04.03.77

II/III

geer, 1774) Tarsia (CS) 14.10.99 III

nzer, 1797) Trionto (CS) 28.06.94 I

ARTICLE IN PRESSA. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221 211

reared to the third stage under controlled temperatureand photoperiod. According to the method ofZetto Brandmayr (1976, 1978), the larval stages ofO. ardosiacus were reared in laboratory and fed onthe Umbelliferae seeds, mostly Daucus carota. While,C. lefebvrei larval stages were fed on snails (Helix sp.).

For scanning electron microscopy (SEM), antennaewere cut and doubly fixed in 3% glutaraldehyde and 1%osmium tetroxide in 0.1M cacodylate buffer pH 7.2–7.3,dehydrated in a graded ethanol series and critical point-dried. After dehydration, they are mounted on stubs,gold coated and examined in a Cambridge Stereoscan100 scanning electron microscope.

For morphometric measurements, a reduced sample(Table 2) of larvae from 11 species belonging to differentbehavioural types was selected. Photographs were takenwith a stereoscope (Zeiss Stemi SV 11 Apo) andacquired by Matrox PC-VCR software (Windows2000). Measurements were taken using Sigma ScanPro 5 Software (SPSSs Inc.). Differences in morpho-metric measurements were tested using non-parametrictest (U Mann–Whitney test) with Statistica 6.0 software(Statsoft Italia SrL).

Ultrastructural investigations were performed onO. ardosiacus. For light microscopy (LM) observations,the samples were fixed in Bouin and stained bymethylene blue vital (0.5% stock solution diluted 1:100in insect saline before use) to evidence bipolar neurons.The solution was injected by means of a fine tipped glasspipette into the basal antennal joint. Diffusion andsuccessful staining occurred within 1 h. Photographs ofthe preparations were immediately taken, to avoidfading, under a Leitz Dialux phase contrast LM.Permanent mounts were obtained by fixation in 12%W/V ammonium molybdate (Alexandrowicz 1954) and

Table 2. Measurements (mean7standard deviation) of the antenn

width

Behavioural types Species Head wid

Surface walkers Carabus lefebvrei 3.20270.

Surface runners Leistus fulvibarbis 0.99470.

Nebria kratteri 2.20870.

Nebria dahli 1.68270.

Nebria germari 1.24670.

Notiophilus rufipes 0.81670.

Soil pore explorers Laemostenus obtusus 1.16470.

Calathus erratus 1.2470.

Calathus mollis 0.91670.

Seed feeders Ophonus ardosiacus 2.22270.

Ophonus sabulicola 2.14670.

Species are investigated in relation to their life style. Means of 5 specimens

subsequent dehydration in ethanol and clearing inxylene. For transmission electron microscopy (TEM),single antennae were removed from the head andimmediately immersed in 3% glutaraldehyde in 0.1Mcacodylate buffer with 5% sucrose pH 7.2–7.3. Theywere then rinsed in cacodylate buffer, post-fixed in 1%osmium tetroxide in 0.1M cacodylate buffer for 1 h at4 1C and rinsed in the same buffer. Dehydration in agraded ethanol series was followed by embedding inepon-araldite (Electron Microscopy Sciences, FortWashington, PA). Thin sections, cut with an UltratomeIIILKB with glass and diamond knives, were subse-quently stained with uranyl acetate and lead citrate andviewed with a Philips EM208 electron microscope at80 kV.

3. Results

3.1. Morphology and morphometry of antennal

sensory appendage

In carabid beetle larvae the antennae are locatedanterolaterally on the head and articulated in fourantennomeres (Fig. 1A). The third antennomere shows acupuliform sensory appendage (sensorium) varying inshape and size in predator (Figs. 2A–I and 3A–E, G)and seed feeder (Figs. 3F, H, I) larvae.

Table 2 summarizes antennal sensory appendagemeasurements for five individuals (third larval stage)of each species. For comparison, height and width of thesensory appendage are related to head width. Thediagram (Fig. 4) shows that the antennal sensoryappendage of all the species is longer than wide

al sensory appendage base width and height related to head

th (mm) Antennal sensory appendage (mm)

Base w/head w Height/head w

051 0.01770.001 0.02570.001

032 0.02370.004 0.03970.007

138 0.01170.002 0.01470.003

042 0.0170.002 0.01670.001

073 0.01570.002 0.02470.002

069 0.02470.002 0.03470.007

099 0.01170.001 0.01970.002

061 0.01170.001 0.01570.002

135 0.01470.004 0.00470.003

108 0.01570.001 0.01370.001

083 0.01270.002 0.01570.002

(III stage) per species are given.

ARTICLE IN PRESS

an

as

m

hw

nA

B

C

Fig. 1. Ophonus ardosiacus larva: I stage. (A) Head scanning electron micrograph, dorsal view; an: antennae, as: antennal sensory

appendage, hw: head width, m: mandible. (B) Antennal sensory appendage scanning electron micrograph. (C) Antennal sensory

appendage stained by methylene blue vital (light microscopy micrograph); n: neurons. Scale bars: 200mm (A), 20 mm (B, C).

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221212

except in C. mollis and O. ardosiacus. The sensoryappendage is smaller in C. lefebvrei than in L. fulvibarbis

(Mann–Whitney test: n1 ¼ n2 ¼ 5, Z ¼ 2.61, Po0.01);while in N. rufipes it is significantly wider than in C.

lefebvrei (Mann–Whitney test: n1 ¼ n2 ¼ 5, Z ¼ 2.61,Po0.01) but there is no significant difference about theheight. The width and the length of the sensorium arenot significantly different in Nebria kratteri, Calathus

erratus, Ophonus sabulicola and N. dahli. The sensoryappendage is significantly longer in L. (A.) obtusus thanin C. erratus (Mann–Whitney test: n1 ¼ n2 ¼ 5,Z ¼ �1.98, Po0.01), N. kratteri and O. sabulicola

(Mann–Whitney test: n1 ¼ n2 ¼ 5, Z ¼ �2.19,Po0.01). In two species belonging to the same genus,N. kratteri and N. germari, there are significantdifferences in width (Mann–Whitney test: n1 ¼ n2 ¼ 5,Z ¼ �2.19, Po0.02) and height (Mann–Whitney test:n1 ¼ n2 ¼ 5, Z ¼ �2.61, Po0.01) of the sensoryappendage; while O. sabulicola has a sensory appendagesignificantly wider than O. ardosiacus (Mann–Whitneytest: n1 ¼ n2 ¼ 5, Z ¼ 2.19, Po0.02).

3.2. Ultrastructure of O. ardosiacus sensory

appendage

O. ardosiacus (Fig. 1A) antennal sensory appendage isa dome-shaped organ located in the third antennalsegment, measuring 29.071.2 (N ¼ 5) mm in height and34.471.5 (N ¼ 5) mm in diameter in third larval stage.Observations by SEM (Fig. 1B) and LM (Fig. 1C) revealthat the antennal sensory appendage consists of acupuliform part implanted on the thickened socketalong its basal circumference, so defining the subcupularspace in which clustered cell bodies are located.

Ultrathin sections (Figs. 5 and 6A, B) show a sensoryorgan covered by cuticle, showing a subcuticular spaceand consisting of 20 morphofunctional units. A doubletof sensory cells surrounded by three accessory ensheath-ing cells forms each unit.

The cuticle (Figs. 5 and 6A) of the third antennomereis 800 nm in thickness with: an epicuticular layer, anexocuticle and a multilayered endocuticle. Above thesocket, the cuticle consists only of the epi- and

ARTICLE IN PRESS

A B C

D E F

G H I

Fig. 2. Scanning electron micrographs of antennal sensory appendages. (A) Carabus lefebvrei lateral view (III stage). (B) Licinus

silphoides frontal view (III stage). (C) Trechus quadristriatus lateral view (II stage). (D) Leistus fulvibarbis lateral view (III stage).

(E) Nebria kratteri lateral view (I stage) (bar 20mm). (F) Nebria germani lateral view (III stage). (G) Nebria dahli lateral view

(III stage). (H) Notiophilus rufipes lateral view (III stage) (I) Typhlotrechus bilimeki frontal view (III stage). Scale bars: 20mm(A, D, E), 10 mm (B), 50 mm (C, F, G, H, I).

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221 213

exocuticular components which are crossed by very thintubular pores, 20–30 nm in diameter, occurring inperiodical series regularly spaced some 30 nm apart(Fig. 6C). Below the cuticle there is a subcuticularelectronlucent wide space (2 mm) in which the canali-cular pores open.

The sensory cells (Figs. 5 and 6A, B), that form thesensory unit, are typical bipolar cells with an ellipsoidalsoma, 12 mm in greatest diameter and 6 mm in lowestdiameter. In the sensory cell body the smooth endo-plasmic reticulum (SER), Golgi complex and lysosomesare found. No stacked rough endoplasmic reticulum(RER) cisternae are noticeable. The subspheric nucleus4 mm in diameter has scanty and sparse heterochromaticlumps. The nucleolus is central and conspicuous. The

neurons basally send off axons, from 0.4 to 0.8 mm indiameter, merging into an unmyelinated sensory nervehowever enveloped by glial cells.

The cell’s dendrite is 50 mm long and it is differen-tiated into two distinct segments, an inner and an outerdendritic segment, by a ciliary constriction 350 nm indiameter.

The relatively short inner dendritic segment runswithin the basal third of the organ. It is 4 mm in diameterand resembles the cell body in cytoplasm contents. Itslongitudinal section shows the ciliary region andabundant organelles, elongated mitochondria, granularvesicles, tubular and vesicular SER cisternae andmicrotubules. The much longer outer dendritic segmentruns within the apical two thirds of the organ. It has a

ARTICLE IN PRESS

A B C

D E F

G H I

Fig. 3. Scanning electron micrographs of antennal sensory appendages. (A) Laemostenus (A.) obtusus lateral view (I stage).

(B) Calathus glabricollis lateral view (II stage). (C) Calathus fuscipes lateral view (I stage). (D) Calathus mollis lateral view

(III stage). (E) Calathus erratus lateral view (II stage). (F) Harpalus (P.) rufipes frontal view (III stage). (G) Poecilus cupreus lateral

view (I stage). (H) Ophonus sabulicola lateral view (II stage). (I) Harpalus tardus lateral view (I stage). Scale bars: 20mm (A, C, D, E,

F, G), 50mm (B), 10mm (H, I).

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221214

mean diameter of 1.5 mm, is extremely electronlucid andis longitudinally run through by microtubules. Scatteredvesicular and tubular cisternae are more densely presentat a proximal level. Apically, the distal dendrite dividesinto many finger-like branches 100–150 nm in diameter,each containing one or more microtubules. These

projections taper further insinuating into and fillingthe subcuticular space. An electrondense, 12 nm thicksheath tightly adjoins the dendrite plasma membraneand ensheathes it to form the basal swelling up to thefirst apical branches. Three cells, an innermost, anintermediate and an outer, envelop the doublet of

ARTICLE IN PRESS

Fig. 4. Measurements of the antennal sensory appendage base width and height related to head width.

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221 215

sensory neurons (Fig. 5). The innermost or thechogencell has its cell body at the same level of the sensory celldoublets. It is associated with each dendrite doublet andenvelops it up to the proximal end of the outer dendriticsegment by means of a cytoplasmic layer 0.5 mm thick onaverage. This cytoplasmic lamina adheres to the apicalinner dendritic segment by means of septate junctions.Distally, many mitochondria and cytoskeletal fibres11 nm in diameter arranged in longitudinal bundles of300 nm thickness, are present. Between dendrite andaccessory cell, a space or primary receptor lymph cavityoccurs. Proximally, the sinuous finger-like projections ofthe accessory cell envelop the outer dendritic segmentsurface and make its sheath. The cytoplasmic projec-tions of the intermediate and outer enveloping cells,interspersed among the sensory doublets, are typicallyelectrondense and include compact mitochondria, lyso-somes, tubular SER cisternae, microtubules and glyco-gen granules. The intercellular space becomes nearlysealed in places by close apposition of plasma mem-branes which form junctional complexes with gap- andintermediate junctions and septate desmosomes. Distallythere are wide lacunar spaces, so called secondaryreceptor lymph cavities. In these, enveloping celllaminar, 40–60 nm thick, projections parallel andstacked make sinuous and whorled profiles. Moreapically, below the cupola, the projections of theenveloping cells swell into bulbous endings surroundedby many laminar layers. In their cytoplasm manymultilaminar bodies with membranes whorls 2 mm indiameter, become apparent. These myelin-like bodiesmay represent evidence of the high membrane turnoverto be related to the large surface area exposed to thereceptor lymph space.

4. Discussion

The antennal sensory appendage of polyphagancoleopteran larvae was investigated by several authors(Scott and Zacharuk 1971; Roppel et al. 1972; Corbiere-Tichane 1971, 1973; Ryan and Behan 1973; Behan andRyan 1978; Bloom et al. 1981). Some of them alsodescribed the ultrastructure and function of a senseorgan located on the second segment: a modified orcompound sensillum basiconicum in structure andolfactory in function. Corbiere (1969) reported itspresence in Bathysciinae (Coleoptera: Cholevidae), andcalled it ‘‘membranous lobe’’ (lobe membraneux);Zacharuk (1962) in Elateridae named it ‘‘antennalsensory appendage’’; Bloom et al. (1981) and Behanand Ryan (1978) identified it as a ‘‘sensillum placo-deum’’ in Tenebrionidae. In carabid beetles thisstructure, firstly called ‘‘hyaline vesicle’’, has beendescribed by van Emden (1942) and Jeannel (1941,1942). It is a small appendage located in a lateralmembranous area of the third antennal segment. Thedifference in location between Polyphaga and Adephagais related to the different number of antennomeres. Thisvariation was examined more in detail by Beutel et al.(1999), who stated the existence of four antennomeres inneuropterids (e.g. Sialidae), in the basic Archostematacoleopterans, in Adephaga and some scarabeids. Inpolyphagan larvae the majority are three-segmented, butin many families the number is reduced to one or two(Lawrence 1991). In the somewhat aberrant, aquatic andminiaturized Myxophaga two-segmented antennaehave been found. Minelli (2004) re-examines in detailthe number of antennal joints in Coleoptera and gives tothe sensorial appendage a sort of ‘‘key-position’’ in

ARTICLE IN PRESS

ax

in

ic

gc

s1

d

od

e

ep

en

ex

so

ss

lc

lc

tp

cuoc

od

idid

s2

s1

s2

Fig. 5. Schematical drawing summarising the ultrastructural features of Ophonus ardosiacus antennal sensory appendage. Black

rectangle highlights a detail of sensory cell unit. ax: axons cu: cuticle; d: dendrite of sensory cell; e: epidermal cell; en: endocuticle; ep:

epicuticle; ex: exocuticle; gc: glial cell; ic: innermost cell; id: inner dentritic segment; in: intercalary cell; lc: lymph cavity; oc: outer

cell; od: outer dentritic segment; s1, s2: sensory cell; so: socket; ss: subcuticular space; tp: tubular pore.

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221216

determining their basic number: three, according toLawrence’s idea.

The sensorial appendage varies also in size and lengthfrom a moderately long appendage to a more or lessshort coniform or cupuliform sensorium (Beutel et al.1999), and it is absent in Sialidae, some hydroadephaganfamilies (Gyrinidae, Noteridae) and many polyphagangroups. Also in Carabidae a trend from a four- to athree-jointed antenna is seen comparing ‘‘normal’’ taxawith the autapomorphic status of Helluomorphoides

larvae (antacoria of antennomeres II–III disappears,Bousquet 1987) and with the fully three-jointed antennaof Anthiini derived by fusion (see Table 3).

About ultrastructure, the antennal sensory appendageof O. ardosiacus is a multiporous structure with a clusterof sensory units. The dendrite outer segments are highly

branched and fray off into thin digitiform projectionsthat increase membrane surface receptor sensitivity tohighly diluted odour stimulants. The occurrence of poretubules extending from the pore inner end to contact thedendrite tip membrane is considered evidence of astimulus conducting mechanism to the dendritic mem-brane molecular receptors (Zacharuk 1980; Steinbrecht1987). Multiporous sensilla with high numbers ofchemosensory neurons – the most commonly foundtype on the antennae and proved olfactory in function –have been described (Corbiere-Tichane 1971; Meinecke1975; Zacharuk 1980, 1985; Altner and Prillinger 1980;Chapman 1982). Moreover, the complex multicellularstructure of the organ suggests a possible ability of fineodour discrimination related to prey choice. This featureis convergent to ‘‘lobe membraneux’’ of Speophyes

ARTICLE IN PRESS

od

d

cu

so

id

A

B

C

Fig. 6. Transmission electron micrograph of Ophonus ardosiacus antennal sensory appendage. (A) longitudinal ultrathin section; cu:

cuticle, d: dendrite, so: socket. (B) Longitudinal ultrathin section of inner (id) and outer dendritic segment (od) highly branched. (C).

Longitudinal ultrathin section of cuticular pores (black headarrow). Scale bars: 1.1 mm (A), 1.7 mm (B), 0.09 mm (C).

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221 217

lucidulus larvae (Coleoptera, Bathysciinae) (Corbiere-Tichane 1973). The pores tubule complex is not reportedby Corbiere-Tichane (1971) and Corbiere (1969) butevidence of pore tubule contacts is technique dependentand may require special fixation (Steinbrecht andMueller 1971).

In carabid larvae, biotic factors (food) are mostimportant in evolution of mandibles form while abioticfactors (soil type and sun radiation) influence generalbody form (Zetto Brandmayr et al. 1998). Moreover,larval species show a difference in number and distribu-tion of the sensorial pattern of maxillary and labialpalps related to feeding habits and use of space (Giglioet al. 2003). More generally, comparing the antennalsensory appendage in the taxa so far described (Table 3and references) it seems that variations in form (conical,reduced or absent) are related to larval feedingbehaviour and mobility. Indeed, a fine olfactive dis-crimination is suggested also by the maximal size of thevesicle found in N. rufipes and L. fulvibarbis (Fig. 4):both are specialized collembolan predators. The sensoryappendage is vestigial or fully reduced in locomotoryless active larvae or stages, e.g. in all the instars ofCarterus calydonius (Brandmayr 1975). This mediterra-nean Harpalinae species shows full-time brood care insubterranean paedotrophic nests, supplied by themother beetle with Daucus seeds. The larvae of thisDitomine remain in the nest, few centimeters away from

the core of the nest, throughout their pre-imaginal life(Brandmayr and Brandmayr Zetto 1974). In parasitoidforms (Brachinus, Pheropsophus, Lebia, Eripus) or antnest predatory inquilines (Graphipterus) the sensoryappendage is wide cupuliform just in the first stage thatis the only highly mobile one in order to reach the host/ant nest, while in the older stages the organ is smaller orquite reduced together with other head appendages(Erwin 1967; Habu and Sadanaga 1965; Liebherr andBall 1990; Zetto Brandmayr et al. 1993; Paarmann1985). In Cicindela larvae, this sense organ is missingand replaced by a sensory area (Breyer 1989). For thisgenus the capability of ambushing the prey by usingburrows as shelters is well known (Schremmer 1979).The sensory appendage is bulbous and as long as theantennomere IV in Paussini myrmecophilus species andconical in Metrius and Ozaenini (Bousquet 1986; DiGiulio et al. 2003).

Morphometric analysis shows no correlation betweenantennal sensory appendage dimension and behaviouraltype. However, there are variations in size of thissensory structure in specialized and unspecializedpredators and active seed feeders that can be related tothe prey-food detection. So, the high number ofchemosensory neurons of this multiporous organsuggests a possible ability of fine odour discrimina-tion related to prey choice or host location. Eventhough, further researches, concerning electrophysiological

ARTICLE IN PRESS

Table 3. Variations in form of the antennal sensory appendage related to the feeding behaviour in carabid’s taxa known and in the

‘‘basic’’ family Trachypachidae

Genus Larval feeding behaviour Antennal sensory appendage References

Cupuliform/conic Reduced/

absent

Modified

Trachypachus

Motschulsky, 1844

Unspecialized predators X Arndt and Beutel 1995

Systolosoma Solier, 1849 Unspecialized Predators X Arndt and Beutel 1995

Omoglymmius

Ganglbauer, 1891

Slime mold feeders?

physogastric

X Grandi 1955; Beutel 1992b

Gehringia Darlington,

1933

Unspecialized predators X Lindroth 1960

Metrius Eschscholtz,

1829

Termites-feeder X Bousquet 1986; Beutel

1992a; Di Giulio et al. 2003

Paussus Linneus, 1775 Myrmecophilous X Di Giulio et al. 2003

Notiophilus� Dumeril,

1806

Collembola-feeders X Altner and Bauer 1982;

Luff 1993

Nebria� Latreille, 1802 Small prey feeders X Luff 1993

Leistus� Froehlich, 1799 Collembola-feeders X Daly and Ryan 1979; Luff

1993

Omophron Latreille,

1802

Unspecialized predators X Beutel 1991

Carabus� Linneus, 1758 Earthworm or snail-feeder X Luff 1993

Opisthius Kirby, 1837 Unspecialized predators ‘‘Inconspicuous’’ Lindroth 1960

Promecognathus

Chaudoir, 1846

Unspecialized predators X Bousquet and Smetana

1986

Cicindela Linneus, 1758 Ambush predators in

burrows

X Luff 1993

Loricera Latreille, 1802 Collembola-feeders X Bauer and Kredler 1988

Elaphrus Fabricius, 1775 Collembola-feeders X Luff 1993

Siagona Latreille, 1804 Ant predator? X Zetto Brandmayr et al.

2007

Scarites Fabricius, 1775 Hard prey feeders, sand

diggers

X Luff 1993

Broscus Panzer, 1813 Unspecialized predators X Luff 1993

Pseudomorpha Kirby,

1825

Ant predator, eruciform X Thompson 1979; Erwin

1981

Sphallomorpha

Westwood, 1841

Ambush ant predator X Moore 1974

Trechus� Clairville, 1806 Unspecialized predators X Luff 1993

Typhlotrechus� Mueller,

1913

Unspecialized predators X Luff 1993

Bembidion Stephens,

1828

Unspecialized predators X Luff 1993

Morion Latreille, 1806 Under-bark predators (?) X Thompson 1979

Poecilus� Bonelli, 1810 Unspecialized predators X Luff 1993

Pterostichus Bonelli,

1810

Unspecialized predators X Luff 1993

Laemostenus� Bonelli,1810

Unspecialized predators X Casale 1988

Calathus� Bonelli, 1810 Unspecialized predators X Luff 1993

Carterus Dejean, 1829 Seed feeder, physogastric X Brandmayr 1975

Ophonus� Stephens,1828

Seed feeders X X Brandmayr et al. 1980; Luff

1993

Harpalus� Latreille,1802 s. l.

Seed feeders or predatory X Brandmayr et al. 1980; Luff

1993

Licinus� Latreille, 1802 Snail-feeders X Luff 1993

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221218

ARTICLE IN PRESS

Table 3. (continued )

Genus Larval feeding behaviour Antennal sensory appendage References

Cupuliform/conic Reduced/

absent

Modified

Graphipterus Forsk(al,

1775

Ant brood predators I stage II–III stages Zetto Brandmayr et al.

1993

Chlaenius Bonelli, 1810 Unspecialized predators X Habu and Sadanaga 1965;

Bonacci et al. 2005

Helluomorphoides Ball,

1951

Ant praedator? ? Thompson 1979; Bousquet

1987

Thermophilum

Basilewski, 1950

Ants and ant brood X Uscidda 1974

Eripus Dejean, 1829 Ectoparasitoids X Liebherr and Ball 1990

Cymindis Latreille, 1806 Unspecialized predators X Luff 1993

Brachinus Weber, 1801 Ectoparasitoids I stage II–III stages Erwin 1967

Pheropsophus Solier,

1833

Ectoparasitoids X Habu and Sadanaga 1965

Lebia Latreille, 1802 Ectoparasitoids I stage II–III stages Habu and Sadanaga 1965;

Luff 1993

�indicate taxa selected in order to give an idea of variation, not for an exhaustive survey. In the seed-eating Ophonus and related taxa we may find

normally developed sensorial vesicles (Ophonus s. str., Metophonus) but also modified, perhaps less-functional forms (Brandmayr et al. 1980). A

similar, kidney-shaped sensorial appendage has been found in Systolosoma lateritium.

A. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221 219

response, are needed to correlate the sensory structure withthe specific odour stimulants.

Acknowledgements

The authors are grateful to Dr. Stefano Sponza forthe helpful discussions in statistical analysis. Thisresearch was funded by a MIUR (ex 60%) grant‘‘Ricerche eco-etologiche e morfofunzionali in Coleot-teri carabidi’’ to T. Zetto.

References

Alexandrowicz, J.S., 1954. Notes on the nervous system in the

Stomatopoda. IV. Muscle receptor organs. Pubbl. Staz.

Zool. Napoli 25, 94–111.

Altner, H., Bauer, T., 1982. Ultrastructure of a specialized,

thrust-sensitive, insect mechanoreceptor: stimulus-transmit-

ting structures and sensory apparatus in the rostral horns of

Notiophilus biguttatus. Cell Tissue Res. 226, 337–354.

Altner, H., Prillinger, L., 1980. Ultrastructure of invertebrate

chemo- thermo, and hygroreceptors and its functional

significance. Int. Rev. Cytol. 67, 69–138.

Arndt, E., Beutel, R.G., 1995. Larval morphology of

Systolosoma Solier and Trachypachus Motschulsky (Co-

leoptera: Trachypachidae) with phylogenetic considera-

tions. Entomol. Scand. 26, 439–446.

Bauer, T., Kredler, M., 1988. Adhesive mouthparts in a

ground beetle larva (Coleoptera, Carabidae, Loricera

pilicornis F.) and their function during predation. Zool.

Anz. 221, 145–156.

Behan, M., Ryan, M.F., 1978. Ultrastructure of antennal

sensory receptors of Tribolium larvae (Coleoptera, Teneb-

rionidae). Int. J. Ins. Morphol. Embryol. 7 (3), 221–236.

Beutel, R.G., 1991. Larval head structures of Omophron and

their implications for the relationships of Omophronini

(Coleoptera: Carabidae). Entomol. Scand. 22, 55–67.

Beutel, R.G., 1992a. Study on the systematic position of

Metriini based on characters of the larval head (Coleoptera:

Carabidae). Syst. Entomol. 17, 207–218.

Beutel, R.G., 1992b. Larval head structures of Omoglymmius

hamatus and their implications for the relationships of

Rhysodidae (Coleoptera: Adephaga). Entomol. Scand. 23,

169–184.

Beutel, R.G., Maddison, D.R., Haas, A., 1999. Phylogenetic

analysis of Myxophaga (Coleoptera) using larval charac-

ters. Syst. Entomol. 24, 171–192.

Bloom, J.W., Zacharuk, R.Y., Holodniuk, A.E., 1981.

Ultrastructure of a terminal chordotonal sensillum in larval

antennae of the yellow mealworm, Tenebrio molitor L. Can.

J. Zool. 59 (3), 515–524.

Bonacci, T., Zetto Brandmayr, T., Brandmayr, P., 2005.

Descrizione della larva di Chlaenius chrysocephalus (Coleoptera

Carabidae). Naturalista Sicil. S. IV, XXIX (3–4), 169–176.

Bousquet, Y., 1986. Description of first-instar larva of Metrius

contractus Eschscholtz (Coleoptera, Carabidae) with re-

marks about phylogenetic relationships and ranking of the

genus Metrius Eschscholtz. Can. Entomol. 118, 373–388.

Bousquet, Y., 1987. Description of the larva of Hellumor-

phoides praestus bicolour Harris with comments on the

relationships of the Helluonini (Coleoptera: Carabidae).

Can. Entomol. 119, 921–930.

Bousquet, Y., Smetana, A., 1986. A description of the first

instar larva of Promecognathus Chaudoir (Coleoptera:

Carabidae). Syst. Entomol. 11, 25–31.

ARTICLE IN PRESSA. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221220

Brandmayr, P., 1975. Note morfologiche sugli studi preimma-

ginali di Carterus (Sabienus) calydonius Rossi (Coleoptera,

Carabidae). Boll. Soc Entomol. It. 107, 9–19.

Brandmayr, P., Brandmayr Zetto, T., 1974. Sulle cure

parentali e su altri aspetti della biologia di Carterus

(Sabienus) calydonius Rossi, con alcune considerazioni

sui fenomeni di cura della prole sino ad oggi riscontrati in

Carabidi (Coleoptera, Carabidae). Redia 55, 143–175.

Brandmayr, P., Ferrero, E., Zetto Brandmayr, T., 1980. Larval

versus imaginal taxonomy and the systematic status of the

ground beetle taxa Harpalus and Ophonus (Coleoptera:

Carabidae: Harpalini). Entomol. Gen. 6 (2/4), 335–353.

Breyer, S., 1989. Skelet und Muskulatur des Kopfes der Larve

von Cicindela campestris L. (Coleoptera, Cicindelidae).

Stuttgarter Beitr. Naturk., Ser. A 438 (60), 1–60.

Casale, A., 1988. Revisione degli Sphodrina (Coleoptera,

Carabidae, Sphodrini). Monografie V, Museo regionale di

Scienze Naturali, Torino.

Chapman, R.F., 1982. Chemoreception: the significance of

receptor numbers. Adv. Ins. Physiol. 16, 247–356.

Corbiere, G., 1969. Ultrastructure et electrophysiologie du

lobe membraneux de l’antenne chez la larve du Speophyes

lucidulus (Coleoptere). J. Ins. Physiol. 15, 1759–1765.

Corbiere-Tichane, G., 1971. Structure nerveuse enigmatique dans

l’antenne de la larve du Speophyes lucidulus Delar. (Coleoptere

cavernicole de la sousfamille des Bathysciinae). Etude au

microscope eletronique. J. Microsc. 10 (2), 191–202.

Corbiere-Tichane, G., 1973. Sur les structures sensorielles et

leurs fonctions chez la larve de Speophyes lucidulus. Ann.

Speleol. 28 (2), 247–265.

Daly, P.J., Ryan, M.F., 1979. Ultrastructure of antennal

sensilla of Nebria brevicollis (Fab.) (Coleoptera: Carabi-

dae). Int. J. Ins. Morphol. Embryol. 8, 169–181.

Di Giulio, A., Fattorini, S., Kaupp, A., Taglianti, A.V., Nagel,

P., 2003. Review of competing hypoteses of phylogenetic

relationships of Paussinae (Coleoptera, Carabidae) based

on larval characters. Syst. Entomol. 28 (4), 509–537.

Emden van, F.I., 1942. A key to the genera of larval Carabidae

(Col.). Trans. R. Entomol. Soc. London 92, 1–99.

Erwin, T.L., 1967. Bombardier beetles (Coleoptera, Carabi-

dae) of North America: Part II. Biology and behavior of

Brachinus pallidus Erwin in California. The Coleopterist’s

Bull., 41–55.

Erwin, T.L., 1981. A synopsis of the immature stages of

Pseudomorphini (Coleoptera: Carabidae) with notes on

tribal affinities and behaviour in relation to life with ants.

The Coleopterist’s Bull. 35 (1), 53–68.

Evans, M.E.G., 1994. The carabid body plan: a functional

interpretation. In: Desender, K., et al. (Eds.), Carabid

Beetles: Ecology and Evolution. Kluwer Academic Publish-

ers, Netherlands, pp. 25–31.

Forsythe, T.G., 1991. Feeding and locomotory functions in

relation to body form in five species of ground beetle

(Coleoptera: Carabidae). J. Zool. Soc. London 223, 233–263.

Giglio, A., Ferrero, E.A., Perrotta, E., Tripepi, S., Zetto

Brandmayr, T., 2003. Ultrastructure and comparative

morphology of mouth-part sensilla in ground beetle larvae

(Insecta, Coleoptera, Carabidae). Zool. Anz. 242, 277–292.

Grandi, G., 1955. Rhysodes germari Ganglb. (Coleoptera

Rhysodidae). Documenti morfologici ed eto-ecologici (XXI

contributo alla conoscenza degli insetti a regime specializ-

zato). Boll. dell’Ist. di Entomol. dell’Univ. Bologna 21,

179–196.

Habu, A., Sadanaga, K., 1965. Illustrations for identification

of larvae of the Carabidae found in cultivated fields and

paddy-fields. Bull. Nat. Inst. Agric. Sci. Japan IIIC (19),

81–216.

Jeannel, R., 1941. Faune de France. Coleopteres Carabique 39,

Lechevalier, Paris.

Jeannel, R., 1942. Faune de France. Coleopteres Carabique 40,

Lechevalier, Paris.

Lawrence, J.F., 1991. Order Coleoptera. In: Stehr, F.W. (Ed.),

Immature Insects, vol. 2. Kendall/Hunt, Dubuque, Iowa,

pp. 144–658.

Liebherr, J.K., Ball, G.E., 1990. The first instar larva of Eripus

oaxacanus Straneo & Ball (Coleoptera: Carabidae: Pelecii-

ni): indicator of affinity or convergence? Syst. Entomol. 15,

69–79.

Lindroth, C.H., 1960. The larvae of Trachypachus Mtsch.,

Gehringia Darl., and Opisthius Kby. (Col. Carabidae).

Opusc. Entomol. XXV (1–2), 30–42.

Luff, M.L., 1993. The Carabidae (Coleoptera) larvae of

Fennoscandia and Denmark. Fauna Entomol. Scand. 27,

1–187.

Luna de Carvalho, E., 1991. Revisao do estudo das larvas de

Carabıdeos Paussinae e de subfamılias afins (Coleoptera,

Adephaga). Elytron 5, 285–310.

Meinecke, C.C., 1975. Riechsensillen und Systematik der

Lamellicornia (Insecta, Coleoptera). Zoomorphologie 82,

1–42.

Minelli, A., 2004. A segmental analysis of the beetle antenna.

Studi Trent. Sci. Nat., Acta Biol. 81, 91–101.

Moore, B.P., 1974. The larval habits of two species of

Sphallomorpha westwood (Coleoptera: Carabidae, Pseudo-

morphinae). J. Aust. Entomol. Soc. 13, 179–183.

Paarmann, W., 1985. Larvae preying on ant broods: an

adaptation of the desert carabid beetle Graphipterus

serrator Forsk(al (Col., Carabidae) to arid environments.

J. Arid Environ. 9, 210–214.

Roppel, R.M., Arbogast, R.T., Zeigler, J.A., 1972. Antennal

sensilla of the larval sawtoothed grain beetle, Oryzaephilus

surinamensis (Coleoptera, Cucujidae). Rev. Can. Biol. 31

(1), 9–20.

Ryan, M.F., Behan, M., 1973. The sensory receptors of

Tribolium larvae. Physiol. Zool. 46 (3), 238–244.

Schremmer, F., 1979. Ethokologische Beobachtungen zum

Wohnrohrenbau bei Larven der mitteleuropaischen San-

dlaufkafer-Art Cicindela silvicola (Coleoptera, Cicindeli-

dae). Entomol. Gen. 5 (3), 201–219.

Scott, D.A., Zacharuk, R.Y., 1971. Fine structure of the

dendritic junction body region of the antennal sensory cone

in a larval elaterid (Coleoptera). Can. J. Zool. 49 (6),

817–821.

Spence, J.R., Sutcliffe, J.F., 1982. Structure and function of

feeding in larvae of Nebria (Coleoptera: Carabidae). Can. J.

Zool. 60, 2382–2394.

Steinbrecht, R.A., 1987. Functional morphology of phero-

mone-sensitive sensilla. In: Prestwich, G.D., Blomquist,

G.J. (Eds.), Pheromone Biochemistry. Academic Press,

New York, pp. 353–384.

ARTICLE IN PRESSA. Giglio et al. / Zoologischer Anzeiger 247 (2008) 209–221 221

Steinbrecht, R.A., Mueller, B., 1971. On the stimulus

conducting structures in insect olfactory receptors. Z.

Zellforsch. Mikrosk. Anat. 117, 570–575.

Thompson, R.G., 1979. Larvae of North American Carabidae

with a key to the tribes. In: Erwin, T.L., Ball, G.E.,

Whitehead, D.R. (Eds.), Carabid Beetles: Their Evolution,

Natural History and Classification. Dr W. Junk BV

Publishers, The Hague, pp. 209–291.

Uscidda, C., 1974. La larva di Megacephala euphratica Latr. e

Dej. e Thermophila sexmaculata (Fabr.). ‘‘Studi Sassaresi’’

Sez. III- Ann. della Fac. di Agraria dell’Univ. Sassari, 22.

Zacharuk, R.Y., 1962. Sense organs of the head of larvae of

some Elateridae (Coleoptera): their distribution, structure

and innervation. J. Morphol. 111, 1–33.

Zacharuk, R.Y., 1980. Ultrastructure and function of insect

chemosensilla. Ann. Rev. Entomol. 25, 27–47.

Zacharuk, R.Y., 1985. Antennae and sensilla. In: Kerkut,

G.A., Gilbert, L.S. (Eds.), Comparative Insect Physiology,

Biochemistry and Pharmacology, vol. 6. Pergamon Press,

Oxford, pp. 1–69.

Zetto Brandmayr, T., 1976. Nutrizione e allevamento di

Carabidi esclusivamente fitofagi: spermofagia larvale di

Ophonus ardosiacus Lutsh. Redia 59, 197–206.

Zetto Brandmayr, T., 1978. Studi sulla fitofagia nei Carabidi:

spermofagia larvale di Ophonus ardosiacus Lutsh. (Coleop-

tera, Carabidae). Atti XI Congresso It. Entomol. Portici-

Sorrento, 59–64.

Zetto Brandmayr, T., Brandmayr, P., Marano, I., Paarmann,

W., 1993. The larva of Graphipterus serrator (Forskal 1775)

(Coleoptera Carabidae Graphipterini): description and

functional morphology. Trop. Zool. 6, 299–312.

Zetto Brandmayr, T., Giglio, A., Marano, I., Brandmayr, P.,

1998. Morphofunctional and ecological features in

carabid (Coleoptera) larvae. Mus. Reg. Sci. Nat. Torino,

449–490.

Zetto Brandmayr, T., Mazzei, A., Talarico, F., Giglio, A.,

Bauer, T., Brandmayr, P., 2007. The larva of Siagona

europaea Dejean, 1826: morphology and collecting techni-

que for a subterranean blind ‘‘running ant killer’’ (Coleop-

tera: Carabidae). It. J. Zool. 74 (3), 239–245.