How predator hunting-modes affect prey behaviour: Capture deterrence inDrosophila melanogaster

Abstract

20!Hunting mode, the distinct set of behavioural strategies that a predator employs while 21! hunting, can be an important determinant of the prey organism's behavioural response. 22!However, few studies have considered how a predator's hunting mode influences anti-23! predatory behaviours of a prey species. Here we document the influence of active hunters 24! (zebra jumping spiders, Salticus scenicus) and ambush predators (Chinese praying 25! mantids, Tenodera aridifolia sinensis) on the capture deterrence anti-predatory 26! behavioural repertoire of the model organism, Drosophila melanogaster. We 27! hypothesized that D. melanogaster would reduce overall locomotory activity in the 28! presence of ambush predators, and increase activity with active hunters. First we 29! observed and described the behavioural repertoire of D. melanogaster in the presence of 30! the predators. We documented three previously undescribed behaviours-abdominal 31! lifting, stopping and retreat-which were performed at higher frequency by D. 32! melanogaster in the presence of predators, and may aid in capture deterrence. Consistent 33! with our predictions, we observed an increase in the overall activity of D. melanogaster 34! in the presence of jumping spiders (active hunter). However, counter to our prediction, 35! mantids (ambush hunter) had only a modest influence on activity. We also observed 36! considerable intra and inter-individual variation in response to both predator types. Given 37! these new insights into Drosophila behaviour, and with the genetic tools available, 38! dissecting the molecular mechanisms of anti-predator behaviours may now be feasible in 39! this system.

Scared fitless: Context-dependent response of fear to loss of predators over evolutionary time in Drosophila melanogaster

“…For instance, in the presence of mantids, the Drosophila showed similar levels of activity as during the absence of mantids. However, an earlier study demonstrated that they spent more time lifting their abdomens as a signal of vigilance (Parigi et al 2014). Unless more time spent lifting led to higher energy expenditure, Elliott et al (a) Total number (mean ± SE) of offspring emerged, and (b) development time (mean ± SE) for the stock (stock population captive for ∼900 generations; grey symbols), control-evolved (wild population held captive within a cage without mantid predators for ∼1000 generations; black symbols), and predator-evolved (wild population held captive within a cage with mantid predators for ∼1000 generations; white symbols) populations.…”

“…The behavioural response of Drosophila to Tenodera sinensis was studied in detail by Parigi et al (2014), who observed that Drosophila increased abdominal bobbing in response to the mantid predator. There was a bimodal response in terms of the time spent grooming and the time spent walking, with most individuals spending more time grooming and walking, and others spending less time (Parigi et al 2014).…”

“…The behavioural response of Drosophila to Tenodera sinensis was studied in detail by Parigi et al (2014), who observed that Drosophila increased abdominal bobbing in response to the mantid predator. There was a bimodal response in terms of the time spent grooming and the time spent walking, with most individuals spending more time grooming and walking, and others spending less time (Parigi et al 2014). Rather than examining particular activities, we were interested in whether exposure to predators increased activity in our stock lines, potentially causing the reduction in energy stores at the end of the non-breeding season for mantidexposed flies.…”

“…The other two lineages were initially collected in 2010 at a vineyard in Fennville, Michigan (Parigi et al 2014). This initial population (from over 500 pairs of D. melanogaster) was then split into three treatments (with four replicates each): control with no predators (control-evolved), mantid predator (predator-evolved), and spider predator (not used in this study).…”

“…Fear responses are typically multimodal, and the effect of fear from the mantid is likely due to a combination of vibrations from the mantid, the scent of the mantid, and the scent of dead flies defecated by the mantid. Previously, we demonstrated that exposing naïve Drosophila to a predator (i) caused increased abdominal lifting, an antipredator behaviour in Drosophila (Parigi et al 2014), (ii) reduced fecundity in the following breeding season, and (iii) quicker offspring development but reduced offspring adult mass (Betini et al 2013;Elliott et al 2016). The impact on offspring development was due to maternal effects from stressed mothers, as offspring did not emerge until the mantids were removed (Elliott et al 2016).…”