Abstracts - Deutsche Zoologische Gesellschaft

Physiology Posters 195P PH.18 - ENInnate Immunity: Manduca sexta eggs are able to cope with parasitism byTrichogramma evanescensMohatmed Abdel-latief, Monika HilkerAngewandte Zoologie/Ökologie derTiere, Freie Universität BerlinInsect eggs are not “lost” when having been parasitized. We could show that about a third ofManduca sexta eggs can survive after having been attacked by the parasitic wasp Trichogrammaevanescens. An analysis of transcription rates of immune-relevant genes of M. sexta indicates thatsurvival of the host eggs is due to successful immune responses. Several cDNAs of immune-relatedgenes were generated from M. sexta eggs by DDRT-PCR, i.e., humoral immune response genes(prophenoloxidase ProPO and prophenoloxidase activating protease I PAP I), a cellular immune responsegene (proparalytic peptide ProPP), and the antimicrobial peptides leureptin (Leu), attacin II(Att-II), cecropin 6 (Cec 6), and gloverin (Glov). Furthermore, two novel genes were identified, i.e.,immulectin –V (IML-V) and like-moricin (L-Mor). Quantitative real time RT-PCR analysis showedthat the IML-V, ProPO, ProPP, and PAP I transcript levels were higher in parasitized eggs comparedto unparasitized ones. Transcription rates of the antimicrobial peptides L-Mor, Leu, and Att II did notchange in response to parasitism, whereas transcription levels of Cec 6 and Glov were down-regulated2 to 3 d after parasitism of freshly laid eggs. Our data demonstrate that M. sexta eggs show differentialimmune responses to egg parasitoids [1]. [1] Abdel-latief, M. and Hilker, M. (2008). Innateimmunity: Eggs of Manduca sexta are able to respond to parasitism by Trichogramma evanescens.Insect Biochem. Mol. Biol. 38: 136-145.P PH.19 - ENImpact of running wheel activity on seasonal adaptations in the Djungarian hamster(Phodopus sungorus)Ines Petri, Frank Scherbarth, Stephan SteinlechnerInstitut für Zoologie, Tierärztliche Hochschule HannoverLike other mammals of the temperate zones, the Djungarian hamster (Phodopus sungorus) exhibitspronounced annual changes in several physiological traits, which are directly induced by photoperiod.In autumn or in response to winter-like short day lengths Phodopus sungorus spontaneouslyreduces food intake and body mass as well as size and activity of the gonads. In addition, a changeinto a whitish winter pelage takes place. Another adaptation to winter is the occurrence of torpor, i.e.a state of hypometabolism accompanied by a drop of the body temperature for several hours duringthe resting phase. In a recent study we showed that hamsters with access to a running wheel increasetheir body weight and do not anymore show a seasonal body weight cycle (Scherbarth et al. 2007).Consequently, running wheel activity was assumed to mask or block some of the photoperiodic responsesto short day. The aim of this study was to investigate whether running wheel activity has aninfluence on other seasonal traits such as testes development, fur colouration and torpor in Phodopussungorus. Hamsters were exposed to artificial short days either with a running wheel or without.Besides the expected increase of body mass in hamsters with access to running wheels we could alsoshow a decelerated testes regression and the absence of torpor. However, running wheel activity didnot influence the fur colour index indicating that the hamsters are still able to perceive, and react to,the short photoperiod.