Prepupal Building Behavior in Drosophila melanogaster and Its Evolution under Resource and Time Constraints

Abstract

Structures built by animals are a widespread and ecologically important ‘extended phenotype’. While its taxonomic diversity has been well described, factors affecting short-term evolution of building behavior within a species have received little experimental attention. Here we describe how, given the opportunity, wandering Drosophila melanogaster larvae often build long tunnels in agar substrates and embed their pupae within them. These embedded larvae are characterized by a longer egg-to-pupariation developmental time than larvae that pupate on the surface. Assuming that such building behaviors are likely to be energetically costly and/or time consuming, we hypothesized that they should evolve to be less pronounced under resource or time limitation. In accord with this prediction, larvae from populations evolved for 160 generations under a regime that combines larval malnutrition with limited developmental time dug shorter tunnels than larvae from control unselected populations. However, the proportion of larvae that embedded before pupation did not differ between the malnutrition-adapted and control populations, suggesting that tunnel length and likelihood of embedding before pupation are controlled by different genetic loci. The behaviors exhibited by wandering larvae of Drosophila melanogaster prior to pupation offer a model system to study evolution of animal building behaviors because the tunneling and embedding phenotypes are simple, facultative and highly variable.

Experimental evolution of post-ingestive nutritional compensation in response to a nutrient-poor diet

“…However, if so, they would have more energy available to spend, e.g. for locomotion; yet, the Selected larvae show reduced locomotor activity [ 51 , 52 ], which suggests that they are more ‘thrifty’ with expending their energy. One might also imagine that the Control larvae might have generated a greater fraction of their energy from amino acid catabolism while saving the carbohydrates.…”

Idiosyncratic evolution of maternal effects in response to juvenile malnutrition in Drosophila

“…where w a is the adult dry weight estimated in the experiment, w e is egg dry weight estimated at 5 μg (Kolss et al ., ), and T is the length of larval growth period estimated as egg‐to‐adult developmental time minus 5 days to account for time needed for egg hatching and metamorphosis. The selected and control larvae do not differ with respect to time spent wandering before pupation (Narasimha et al ., ) or in the length of the pupal period (R. K. Vijendravarma, unpublished data).…”

Adaptation to Chronic Nutritional Stress Leads to Reduced Dependence on Microbiota in Drosophila melanogaster

“…Final size was the mean dry weight of adults, and initial size was assumed to be 0.005 mg, the approximate dry weight of an egg ( 10 ). Time available for growth was estimated as the egg-to-adult time minus 48 h to account for the time needed for egg hatching, the fact that pupae were scored at 24-h intervals, and the time that the larvae spend wandering before pupation (which does not differ between the Selected and Control populations [ 31 ]). While this estimate is necessarily approximate, all conclusions about growth rate were robust to changing the time available for growth by ±24 h.…”