TY - JOUR

T1 - Predatory behaviour of some Central European pselaphine beetles (Coleoptera: Staphylinidae: Pselaphinae) with descriptions of relevant morphological features of their heads

AU - Schomann, Andrea Maria

AU - Afflerbach, Kerstin

AU - Betz, Oliver

PY - 2008

Y1 - 2008

N2 - The Pselaphinae is a large subfamily of staphylinid beetles with a characteristic habitus and small body size. Detailed morphological and behavioural studies on these beetles are scarce. In this study, specimens of Bryaxis puncticollis (Denny, 1825), Bryaxis bulbifer (Reichenbach, 1816), Bythinus burrelli (Denny, 1825), Brachygluta fossulata (Reichenbach, 1816), Rybaxis longicornis (Leach, 1817), Pselaphus heisei (Herbst, 1792) and Tyrus mucronatus (Panzer, 1803), all collected in Northern Germany, have been examined with regard to their sensory organs (eyes and antennae), mouthparts and method of capturing prey. Scanning electron microscope studies revealed sex-specific differences in the numbers of ommatidia in Bryaxis puncticollis. A multitude of different sensilla on the antennae and great differences in the shape of the mouthparts were observed and peculiarities of the antennae and maxillary palps (e.g., the segment-like appendage) were examined using scanning and transmission electron microscopy. The prey-capture behaviour of these species is described in detail for the first time based on laboratory experiments using Heteromurus nitidus (Templeton, 1835) (Collembola) as prey. This behaviour seems to be tribe specific, ranging from simple seizure with the mandibles (e.g., Rybaxis longicornis, tribe Brachyglutini) to the employment of raptorial legs (Tyrus mucronatus, tribe Tyrini). The two Bryaxisspecies (tribe Bythinini) even employ their apparently sticky maxillary palps to capture prey. The assumption that a viscous secretion is used by these species is supported by the finding of glandular structures in the interior of their maxillary palps. Prey-capture is preceded by a complicated preparation phase in most of the species and followed by a sequence of prey-handling movements that seem to be adapted to restrain prey such as Collembola. In simple prey-choice experiments the beetles of several species preferred small prey, irrespective of their own body size. In these experiments, Bryaxis bulbifer and Brachygluta fossulata were more successful in capturing prey than Bryaxis puncticollis and Pselaphus heisei. This might be related to their different sensory equipment and different methods of capturing prey.

AB - The Pselaphinae is a large subfamily of staphylinid beetles with a characteristic habitus and small body size. Detailed morphological and behavioural studies on these beetles are scarce. In this study, specimens of Bryaxis puncticollis (Denny, 1825), Bryaxis bulbifer (Reichenbach, 1816), Bythinus burrelli (Denny, 1825), Brachygluta fossulata (Reichenbach, 1816), Rybaxis longicornis (Leach, 1817), Pselaphus heisei (Herbst, 1792) and Tyrus mucronatus (Panzer, 1803), all collected in Northern Germany, have been examined with regard to their sensory organs (eyes and antennae), mouthparts and method of capturing prey. Scanning electron microscope studies revealed sex-specific differences in the numbers of ommatidia in Bryaxis puncticollis. A multitude of different sensilla on the antennae and great differences in the shape of the mouthparts were observed and peculiarities of the antennae and maxillary palps (e.g., the segment-like appendage) were examined using scanning and transmission electron microscopy. The prey-capture behaviour of these species is described in detail for the first time based on laboratory experiments using Heteromurus nitidus (Templeton, 1835) (Collembola) as prey. This behaviour seems to be tribe specific, ranging from simple seizure with the mandibles (e.g., Rybaxis longicornis, tribe Brachyglutini) to the employment of raptorial legs (Tyrus mucronatus, tribe Tyrini). The two Bryaxisspecies (tribe Bythinini) even employ their apparently sticky maxillary palps to capture prey. The assumption that a viscous secretion is used by these species is supported by the finding of glandular structures in the interior of their maxillary palps. Prey-capture is preceded by a complicated preparation phase in most of the species and followed by a sequence of prey-handling movements that seem to be adapted to restrain prey such as Collembola. In simple prey-choice experiments the beetles of several species preferred small prey, irrespective of their own body size. In these experiments, Bryaxis bulbifer and Brachygluta fossulata were more successful in capturing prey than Bryaxis puncticollis and Pselaphus heisei. This might be related to their different sensory equipment and different methods of capturing prey.

KW - Faculty of Science

KW - Staphylinidae

KW - Pselaphinae

KW - Brachygluta

KW - Bryaxis

KW - Bythinus

KW - Pselaphus

KW - Rybaxis

KW - Tyrus

KW - predatory behaviour

KW - prey-capture

KW - morphology

KW - head

KW - antenna

KW - mouthparts

KW - maxillary palp

KW - sensillum

KW - sensory organ

M3 - Journal article

VL - 105

SP - 889

EP - 907

JO - European Journal of Entomology

JF - European Journal of Entomology

SN - 1210-5759

IS - 5

ER -