Sequential Analysis Reveals Behavioral Differences Underlying Female-Biased Predation Risk in Stalk-Eyed Flies

Abstract

Stalk‐eyed flies are classic models of how sexual selection can drive morphological and behavioral elaboration. Exaggerated ornaments born by stalk‐eyed flies could impose locomotor costs and increase susceptibility to predation; however, a previous study determined that behavior, not eye span, was the major influence on predation risk. Despite the importance of behavior, relatively little is known about how these flies avoid and deter predators. We created an ethogram of behaviors and used it to score individual interactions of male and female Teleopsis dalmanni paired with an actively foraging, generalist arachnid predator (Phidippus audax). Sequential analysis was employed to identify temporal patterns in behavior and determine how males and females differ in their approaches to avoiding predation. Our results indicate that males and females significantly differ when specific behaviors were employed. Patterns in the behavioral transitions suggest that males are more aggressive than females and are more likely to approach a predator to jab, abdomen bob, or display. Males elicited more retreat responses from the predator, whereas females elicited more attacks. Although the behavioral repertoires of male and female stalk‐eyed flies are indistinguishable, their uses of the behaviors differ, particularly the sequential order of presentation, suggesting a strong sex difference in anti‐predatory behavior.

Dyadic behavioural interactions in cockroaches (Blaberidae): ecomorphological and evolutionary implications

“…When two individuals display a similar behavioural act in two different contexts, this should not be interpreted as perfectly equivalent. Hence, considering transitions among behavioural acts within a sequence, and not only behavioural repertoire, is important to characterize behavioural interactions (Bakeman & Gottman, 1997;Legendre et al, 2008b;Worthington & Swallow, 2011).…”

Characterisation of Predator‐Directed Displays in Tephritid Flies

“…When a tephritid fly encounters a salticid, it usually displays to the salticid, with the result that the salticid either retreats or performs a territorial or courtship display in response (Greene et al 1987; see also Worthington & Swallow (2011) for a non-tephritid fly). This phenomenon has been termed 'predator mimicry', with the argument that the fly mimics the appearance and courtship or territorial displays of salticid predators (Eisner 1985;Greene et al 1987;Mather & Roitberg 1987; see also Rota et al (2006)).…”

Size matters, but so does shape: quantifying complex shape changes in a sexually selected trait in stalk-eyed flies (Diptera: Diopsidae)

“…Studies investigating the flight performance trade‐offs between males and females have found minor or no differences in aerial performance (Swallow, Wilkinson & Marden, 2000; Ribak & Swallow, 2007), despite predictions that males should suffer from decreased aerial maneuverability compared with females (Swallow et al ., 2000). Substantiating these results on performance, in staged laboratory interactions with a predator, indicate that males exhibit higher survival when facing a predator than do females (Worthington & Swallow, 2010; Worthington & Swallow, 2011). Reasons for this lack of a trade‐off have largely been attributed to morphological compensation by flight musculature and wing size, with males exhibiting significantly larger thoracic masses (Swallow et al ., 2000; Ribak & Swallow, 2007) and wing sizes (Ribak et al ., 2009b; Husak et al ., 2011; Husak & Swallow, 2011) than females.…”