the food ingestion process in Nebria (Latreille, 1802)
and the role of maxillary palp sensilla. The sensory
complement of Graphipterus serrator (Forskål, 1775)
larvae, which demonstrate a myrmecophagous life-
style, was also described in detail (ZETTO BRANDMAYR
et al. 1993).
To our knowledge, no additional morphofunctional
information on sensory structures has been published,
despite the large number of larvae described for sys-
tematic purposes by means of scanning electron
microscopy (ERWIN 1981; LIEBHERR & BALL 1990;
BREYER 1989; LANDRY & BOUSQUET 1984; BOUSQUET
& GOULET 1984; BEUTEL 1991).
In a previous study (ZETTO BRANDMAYR et al. 1998),
the adaptive value of different morphological patterns
in carabid larvae was considered, taking into account
the mandibles with their mandibular muscles, the gen-
eral body form and the urogomphi. Their modifications
were linked to nine different “morphoecological
types”. The aim of the present research is to investigate
whether a corresponding diversity is also found in the
sensory equipment, particularly on the maxillary and
1. INTRODUCTION
In carabid larvae, as in most of the coleopteran larvae,
a large number of sensory structures is located on the
labial and maxillary palps, as these appendages are
directly involved in the detection and recognition of
food or prey by means of both tactile and chemical
receptors.
The sensory complement of palps was previously stud-
ied in polyphagous beetle larvae such as Tenebrio
molitor (BLOOM et al. 1981, 1982 a, b), Tribolium
(BEHAM & RYAN 1978), Oryzaephilus surinamensis
(ROPPEL et al. 1972), Entomoscelis americana (MIT-
CHELL et al. 1979), Speophyes lucidulus (CORBIÈRE
1969; CORBIÈRE-TICHANÈ 1973) and Ctenicera
destructor (ZACHARUK 1962, 1971, 1979; ZACHARUK et
al. 1977).
With regards to carabid beetle larvae, descriptions of
the rostral processes of Notiophilus biguttatus (Fabri-
cius 1779) (ALTNER & BAUER 1982), Loricera pilicor-
nis (Fabricius, 1775) (BAUER & KREDLER 1988) are
available, while SPENCE & SUTCLIFFE (1982) described
0044-5231/03/242/03-277 $ 15.00/0
Ultrastructure and Comparative Morphology
of Mouth-part Sensilla in Ground Beetle Larvae
(Insecta, Coleoptera, Carabidae)
Anita GIGLIO
1
, Enrico A. FERRERO
2
, Enrico PERROTTA
1
, Sandro TRIPEPI
1
and Tullia ZETTO BRANDMAYR
1
1
Department of Ecology, University of Calabria, Arcavacata di Rende, CS, Italy
2
Department of Biology, University of Trieste, Italy
Abstract. Labial and maxillary palps in 22 species of ground beetle larvae revealed the presence of four different
types of sensilla: sensilla digitiformia, sensilla campaniformia, sensilla basiconica and sensilla chaetica. Using
transmission electron microscopy techniques, the role of most of them was defined: sensilla campaniformia and
sensilla chaetica are mechanoreceptors; while sensilla basiconica are chemoreceptors. Sensilla digitiformia can be
both mechanoreceptors and chemoreceptors, though hygroreception may also be postulated on the basis of their
abundance on the mouthparts of some hygrophilous species that depend on damp or wet patchy biotopes/seasons.
The number and location of the sensory structures has been found to vary among the investigated taxa. The differ-
ences are related to the larval behavioural types, and are an adaptive response to different lifestyles, feeding habits
and use of space.
Key words. Larval sensory patterns, larval behavioural types, feeding behaviour, ultrastructure.
Zool. Anz. 242 (2003): 277–292
© by Urban & Fischer Verlag
http:/ / www.urbanfischer.de/ journals/ zoolanz