DOI: 10.5061/dryad.xgxd254fm
title: Tests of search image and learning in the wild: insights from sexual conflict in damselflies

description: Search image formation, a proximal mechanism to maintain genetic
 polymorphisms by negative frequency-dependent selection, has rarely been
 tested under natural conditions. Females of many non-territorial
 damselflies resemble either conspecific males or background vegetation.
 Mate-searching males are assumed to form search images of the majority
 female type, sexually harassing it at rates higher than expected from its
 frequency, thus selectively favoring the less common morph. We tested this
 and how morph coloration and behavior influenced male perception and
 intersexual encounters by following marked Ischnura elegans and noting
 their reactions to conspecifics. Contrary to search image formation and
 associative learning hypotheses, although males encountered the minority,
 male-like morph more often, sexual harassment and clutch size were similar
 for both morphs. Prior mating attempts or copulas with morphs did not
 affect a male’s subsequent reaction to them; males rarely attempted
 matings with immature females or males. Females mated early in the day,
 reducing the opportunity for males to learn their identity beforehand.
 Once encountered, the male-like morph was more readily noticed by males
 than the alternative morph, which, once noticed was more likely to receive
 mating attempts. Flexible behavior gave morphs considerable control over
 their apparency to males, influencing intersexual encounters. Results
 suggested a more subtle proximal mechanism than male learning maintains
 these color polymorphisms and call for inferences of learning to be
 validated by behavior of wild receivers and their signalers.
description: We followed marked focal males and color polymorphic focal
 females in the wild for as long as possible,  recording all interactions
 with conspecifics and the behaviors during those interactions. Females are
 either colored like males (andromorphs, A-morphs) or are more similar in
 coloration to background vegetation (heteromorphs, H-morphs). We inferred
 perception and intent of focal individuals from their behavioral responses
 to conspecifics.  Additionally we did censuses of
 individuals to measure the frequency of female color morphs in the
 population, and of copula pairs to understand the availability of
 potential mates across the day. We followed egg-laying females to see
 whether they got harassed by males, and collected eggs from females
 directly after copula ended, to determine whether one morph had higher
 clutch size than the other.  We used GLMM models to
 determine: 1) if males encountered the majority H-morph
 more often than expected given its frequency  (70%) in the
 population.  2) if males correctly recognized
 conspecifics (i.e. H- and A-morphs) as potential mates and recognized
 immature females and males as  inapproriate for mating.  
 3) to determine if focal female morphs differed in their
 behavioral responses to males We used GLM models to
 determine: 4) to test whether males perceived the two
 morph types differntly 5) to test whether the two morph
 types received different rates of sexual harassment by males
 6) to test for unexpected deviations between intersexual
 encounters of focal males and focal females We analyzed
 the data on focal male behavior using a markov model to identify
 behavioral transition states of focal males, and then tested those
 transitions to see if they agreed with the expected assumption that males
 recognized conspecifics based on their past experience with them (i.e.
 associatively learned or formed search images to recognize color
 polymorphic females as mates, and whether they learned to avoid to males
 and immature females as potential mates. 
description: Notes on variables are in all excel files. For GLM and GLM
 analyses, R-code is submitted under a file entitled
 'Analysis_Dryad'.