Tests of search image and learning in the wild: Insights from sexual conflict in damselflies

Abstract

A major question in evolutionary biology is how natural selection maintains genetic variation in populations (Lewontin, 1974). One commonly cited proximal mechanism for maintaining multiple genotypes is negative frequency-dependent selection by search image formation (Tinbergen, 1960, reviewed by Punzalan et al. 2005, here defined as a short-term, perceptual bias in cueing to a given phenotype while ignoring alternative ones. For example, genetic color polymorphisms in cryptic prey species are thought to evolve because

Different stress from parasites and mate choice in two female morphs of the blue-tailed damselfly

“…Our results on female pairing are in line with two other studies on the Blue-tailed damselfly, where a preference for gynochrome females was also found Sánchez-Guillén et al 2017), but differs from other studies where males did not prefer gynochrome females but mated predominantly with the most common morph in the population (van Gossum et al 1999). In general, male-female interactions may be very complex (Cordero et al 1998;Cordero-Rivera and Sánchez-Guillén 2007;Sánchez-Guillén et al 2013a), and may involve image search ability and learning (Punzalan et al 2005;Nityananda 2016; but see Piersanti et al 2021), multiple sensory cues (Van Gossum et al 2008;Winfrey & Fincke 2017;review in Rebora et al 2018), and female behaviour in responding to mating attempts by males. Recent studies report that the preference for a specific morph may not be innate, but that male preference can be influenced by experience, i.e.…”

To harass or to respect: the economy of male persistence despite female refusal in a damselfly with scramble mate competition

“…Although we also detected a color morph effect and a morph by treatment interaction for both female responses to male detections and male reactions to female refusal signals, due to the small sample sizes and the unnatural visual background of the insectary screen, which can unnaturally bias the signal apparency of female morphs (see Fincke, 2015), we cannot draw biological meaningful conclusions from those results. Due to their color differences and the context in which the green and blue females are encountered (Schultz & Fincke, 2013;Fincke, 2015), under natural conditions, relative to blue females, green females are less likely to be detected by males, but once detected, are more likely to be recognized as potential mates (Piersanti et al, 2021).…”

“…Instead, there is high level of scramble competition among males for females and male mating harassment is common under natural conditions (e.g. Fincke, 2015;Piersanti et al, 2021;Sánchez-Guillén et al, 2017;Van Gossum et al, 2001). Thus, our results offer the novel insights that Parker's (1974) prediction is not only applicable to different mating systems, but that high levels of male-male competition for mates resulting in intense sexual conflict does not completely override the economic principles that govern male reactions to refusal signals.…”

“…Specifically, wing spread was more commonly displayed than head turning both before and after oviposition and males frequently persisted following wing spread in both treatments (Figure 4a, b), suggesting low effectiveness in deterring males by wing spread. Wing spread has been reported in numerous damselfly species (reviewed by Corbet, 1999) and is used not only by mature females but by males and immature females to repel male advances across different contexts (Piersanti et al, 2021;Sánchez-Guillén et al, 2017;Waage, 1984). The effectiveness of these signals also varies both among and within species (Waage, 1984;see Fincke, 1987, for its probable use in mate solicitation).…”

“…Under natural conditions, upon encountering an approaching male, females can prevent being detected by using avoidance behaviors such as hiding by moving to the other side of a stem, or flying away (Fincke, 2015;Piersanti et al, 2021;Sánchez-Guillén et al, 2017). After detection by a male, those same behaviors can also prevent males from persisting in harassment (Piersanti et al, 2021). Females also show two types of refusal signals, which are distinct from the above avoidance behaviors because neither removes the opportunity for males to persist.…”