Antipredator Responses of Larval Black Flies (Simulium Vittatum S. S.) to Chemical Stimuli from Damaged Conspecifics
Sullivan, Aaron M., Miedema, Kristina L., Hiers, Amanda G., Hummelman, Johanna S., Damcott, Johanna A., The American Midland Naturalist
ABSTRACT.-Simulium larvae perform two behaviors in response to physical contact with invertebrate predators: curling and drifting. Curling involves the attachment of a silk thread to the substrate (in preparation for drifting), and drifting allows an individual to quickly leave the vicinity of the predator. The purpose of this study is to determine if larval black flies (Simulium vittatum s. s.) from two field sites respond to chemical stimuli from damaged conspecifics in a manner consistent with responses to predator contact. In experiment 1, we observed die responses of individual S. vittatum to chemicals from damaged members of their own population (Houghton Creek or Sixtown Creek). In experiment 2, we examined larval responses to chemicals from damaged individuals from both sites in order to determine if larvae adjusted their responses based on the source of the stimulus. The results of experiment 1 show that larvae from each population are significandy more likely to engage 'curling' when exposed to damaged conspecifics versus a control. In addition, the duration of the curling behavior was significantly longer when exposed to chemicals from damaged conspecifics compared to a control. The results of experiment 2 demonstrate that individual larvae are more likely to curl when exposed to damaged conspecifics as compared to a control, regardless of the source population of the stimulus donors. We again found that the duration of the curling behavior was significandy longer when exposed to the damaged conspecifics versus the control with no significant difference in the responses to the different source populations. These results offer preliminary evidence to suggest that larval S. vittatum are able to detect and respond to chemicals associated with predation in a natural setting and that there does not appear to be population differences with regard to the nature of the response or the stimulus.
Prey species may reduce a successful prédation event through a variety of antipredator behaviors (Lima and Dill, 1990). However, these behaviors may be cosdy in terms of diminished foraging (Sih, 1980; Abrahams and Dill, 1989; Maerz et al, 2001) or reproduction (Polis et al, 1998; Kokko and Ruxton, 2000). In order to balance diese conflicting demands, prey may adjust the intensity of dieir responses based on the threat levels that they perceive. According to the threat-sensitivity hypothesis, the intensity of prey responses should be positively correlated with the level of threat that they perceive (Sih, 1986; Helfman, 1989). Studies of threat-sensitivity show that prey may adjust their antipredator behavior in response to the number or identity of predators as well as the concentration of cues from prédation events (Kats et al, 1994; Putditz et al, 1999; Mathis and Vincent, 2000; Amo et al, 2004). For instance, Kusch et al. (2004) show that fathead minnows (Pimephales promelas) exposed to cues from predatory pike (Esox ludus) increase their antipredator behaviors (e.g., dashing, freezing, shelter use) as the concentration of chemical stimuli from pike increases. Additional studies in aquatic organisms demonstrate a similar behavioral trend in response to increased concentrations of cues related to predation (Dupuch et al, 2004; Ferrari et al, 2005; Kesavaraju et al, 2007).
Predator-prey interactions involving aquatic macroinvertebrates exhibit a diversity of defensive responses and also demonstrate die tradeoffs associated with antipredator decision making (Lima and Dill, 1990; Dicke and Grostal, 2001). Among aquatic insects, die behavioral and life-history responses of larval ephemeropterans (Malmqvist and Sjöström, 1987; Peckarsky, 1996; Vance-Chakraft et al, 2004) and trichopterans (Fairchild and Holomuzki, 2005; Gall and Brodie, 2009) have been especially well-documented. For instance, studies conducted in natural stream habitats show that larval ephemeropterans increase drifting behavior …
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Publication information: Article title: Antipredator Responses of Larval Black Flies (Simulium Vittatum S. S.) to Chemical Stimuli from Damaged Conspecifics. Contributors: Sullivan, Aaron M. - Author, Miedema, Kristina L. - Author, Hiers, Amanda G. - Author, Hummelman, Johanna S. - Author, Damcott, Johanna A. - Author. Journal title: The American Midland Naturalist. Volume: 166. Issue: 1 Publication date: July 2011. Page number: 75+. © 1995 University of Notre Dame, Department of Biological Sciences. Provided by ProQuest LLC. All Rights Reserved.
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