Residual vitellus and energetic state of wolf spiderlings Pardosa saltans after emergence from egg-sac until first predation

GARCIA, F.; LAINO, A.; TRABALON, M.; CUNNINGHAM, M.

JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2020 vol. 190 p. 261 - 274

0174-1578

The aim of this study was to evaluate energetic source used by juveniles of a terrestrial oviparous invertebrate during theearliest periods of their life. Growth, behavioural activities and energy contents of Pardosa saltans spiderlings? residualvitellus were monitored during 8 days after their emergence from their egg-sac until they disperse autonomously. The lifecycleof juvenile after emergence can be divided into three periods: a gregarious while juveniles are aggregated on theirmother, dismounting off their mother?s back and dispersion. We present the first biochemical study of residual vitellus andenergy expenditure during these three periods. At emergence, the mean weight of juveniles was 0.59 mg and energy stockfrom residual vitellus averaged 51 cal/g wet mass. During gregarious period, the weight of the juveniles aggregated on theirmother did not vary significantly and juveniles utilized only 1 cal/day from their residual vitellus. During the period fromdismounting until their first exogenous feed, juveniles lost weight and used 30% of their residual vitellus stock. Proteins fromthe residual vitellus contributed principally to their energy expenditure during this period: 1.5 μg protein/day. Juveniles? firstexogenous feeding was observed 7?8 days after emergence, when 70% of residual vitellus energy had been utilized. Juvenilesdispersed after eating, reconstituting an energy stock comparable to that observed at emergence from egg-sac (50 cal/g wetmass). This new energy stock contains mainly lipids unlike the energy stock from the residual vitellus.