Moths n’ Stuff Jessica and Alanna

What determines lek size What determines lek size? Cognitive constraints and per capita attraction of females limit male aggregation in an acoustic moth Alem et al.

Review Studied lek behaviour in the lesser wax moth Examined factors that may limit lek size Showed preference for leks Stopped selecting leks > 7 males neurological constraints per capita attractiveness

Introduction Discuss many factors that may limit lek size A lek that is too large may be associated with Disease High stress Attractiveness to predators Long time spent travelling to aggregation Female harassment Difficulty evaluating male quality

Introduction “There has been relatively little empirical study of the factors limiting lek size” Justification for their study Referenced many studies that have examined this Do not incorporate these factors into study interact with neurological constraints or attractiveness?

Introduction Purpose is clear: No clear hypotheses or predictions Per capita male attractiveness Tendency of males to aggregate Mechanisms in which females distinguish leks and assess their size No clear hypotheses or predictions

Introduction Should have included information about the test species in the introduction Male and female behaviour related to singing Male and female mating behaviour Components of male song Female preferences All included in methods Information regarding male aggression?

Methods Alem et al. 2011 They suggest that avoidance of predation may be a reason for leks “However, the range of group sizes tested in that study (two to four males) was too limited to allow any determination of the limits on lek size, and the specific tendency of males to form leks was not investigated” So, they bring up a potential reason for leks, then invalidate it and don’t investigate further

Methods Moths were taken from two populations Tours, Dept Indre et Loire, France Kansas U.S.A. We recognize the potential for differences between A. grisella populations in the shape of the preference function and in the threshold of response to pulse pair rates ... . However, females in the two populations show similar preferences for more extravagant signals and we therefore assumed that the general mechanism of lek discrimination was conserved. To confirm this assumption, we also sampled several Indre et Loire insects in tests distinguishing leks from solitary males and compared these supplementary observations with the kansas pop.

Methods “Additionally, pulse pair rhythms of Indre et Loire and Kansas solitary males were not statistically different (t49 = 1.97, P = 0.064)” It would be considered significantly different at P=0.05 “Accordingly Indre et Loire females might show a decelerating preference for larger leks comparable to the preference observed in Kansas females”

Experiment 1 Female Preference for Leks of Singing Males The spacing of the experiment cages were strange Moths could hear up to one meter away but the cages were only 24 cm away

Experiment 2 Marginal Female Preference for Larger Leks Per capita attractiveness = # of times the female chose this lek / # of males This doesn’t seem as biologically relevant - females will often show a preference for “superior” males as stated before by the paper

Experiment 3 The Distinguishing Acoustic Features of Leks Increase in pulse pair rhythm for males singing in leks compared to solitary males Difference of 10% +/- 8.5% Increase may have only been 1.5% role of different populations? they didnt separate them

Experiment 3 Lek = 3 males Characteristics of male song different when in larger sized groups? If they are arguing that larger leks produce a song that females cannot distinguish from smaller leks Wouldn’t they be interested in the differences between these two? e.g./ 5 males vs 7 males?

Experiment 4 How Do Females Discriminate Leks from Solitary Males? Tests are redundant Lek vs solitary with recorded and lek vs solitary with synthetic song could establish preference based on just sound and determine the lek size where females stop perceiving the differences

Experiment 4 Could have done something similar to Experiments 1 and 2 with just the recorded song Examine female preference and the lek size in which females stop perceiving the differences in regards to just neurological stimuli (sound)

Experiment 4 Females showed preference for recorded lek song over solitary song But showed no preference when song was synthetic Conclude: females distinguish leks by song but do not evaluate this feature Don’t address the fact that maybe their synthetic song wasn’t biologically accurate if theyre showing a preference doesnt that mean they are evaluating??

Experiment 5 Do Singing Males Join Other Male Singers? Males did not show a significant preference for larger leks and were not repelled from larger leks female preference via neurological perception, attractiveness, etc Draw little picture

Experiment 5 Claim female preference is what determines lek size But, males are showing no preference for any lek sizes! Are the females really influencing size? This is an issue that is not addressed female preference via neurological perception, attractiveness, etc Draw little picture

Discussion “However, males did not exhibit any significant trend to join aggregations of a specific size, and we found no evidence suggesting that larger male groups repelled additional males from arriving and joining them” Seems contradictory to their other results - male attractiveness plateaus …

Discussion “We did not observe any evidence suggesting that larger male groups repelled additional males from arriving and joining them. However, were all males free to move in the arena and interact directly with each other, it is likely that aggression, which is commonly observed among A. grisella males would have occurred and prevented large (5), stable groups from persisting.” Aggression was not mentioned until now This is a potential design flaw

Overall: Important considerations were not taken into account Aggression of the males Using two totally different populations Setup does not resemble natural setting