Developmental plasticity affects sexual size dimorphism in an anole lizard

This is the peer reviewed version of the following article: Bonneaud, C., Marnocha, E., Herrel, A., Vanhooydonck, B., Irschick, D. J., Smith, T. B. (2015), Developmental plasticity affects sexual size dimorphism in an anole lizard. Functional Ecology, which has been published in final form at 10.1111/1365-2435.12468. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving: http://olabout.wiley.com/WileyCDA/Section/id-820227.html#termsSummary While developmental plasticity has been shown to contribute to sexual size dimorphism (SSD) in laboratory studies, its role in shaping SSD variation in wild vertebrate populations is unclear. Here we use a field study and a laboratory experiment to show that resource availability influences the degree of SSD among insular populations of Anolis sagrei lizards in the Bahamas. Total amounts of food biomass explained variation in male, but not female, body size on six Bahamian islands, giving rise to significant differences in SSD. Laboratory experiments on a captive colony of A. sagrei confirmed that variation in SSD was mediated by the effects of prey biomass on developmental plasticity in males, but not females. Indeed, males grew faster and attained larger sizes as adults under high-food treatments than under restricted diets, whereas adult females retained similar body sizes under both conditions. Our results indicate that the amount of food available can influence intersexual variation in body size within a vertebrate species. Sex-specific developmental plasticity may be favoured if it allows individuals to take advantage of varying levels of food opportunities offered by different habitats, by reducing competition between the sexes. As such, plasticity in response to food availability may have played a role in the invasion success of A. sagrei. This study adds to our growing understanding of the effect of resource availability in shaping SSD in reptiles and lends further support to the condition-dependent hypothesis, according to which the larger sex should display greater plasticity in growth in response to environmental conditions.Marie Curie Reintegration GrantUnited States Environmental Protection AgencyUCLA Department of Ecology and Evolutionary BiologyFund for Scientific Research (FWO-Vl), BelgiumNational Science Foundatio

Data from: Developmental plasticity affects sexual size dimorphism in an anole lizard

While developmental plasticity has been shown to contribute to sexual size dimorphism (SSD) in laboratory studies, its role in shaping SSD variation in wild vertebrate populations is unclear. Here we use a field study and a laboratory experiment to show that resource availability influences the degree of SSD among insular populations of Anolis sagrei lizards in the Bahamas. Total amounts of food biomass explained variation in male, but not female, body size on six Bahamian islands, giving rise to significant differences in SSD. Laboratory experiments on a captive colony of A. sagrei confirmed that variation in SSD was mediated by the effects of prey biomass on developmental plasticity in males, but not females. Indeed, males grew faster and attained larger sizes as adults under high food treatments than under restricted diets, whereas adult females retained similar body sizes under both conditions. Our results indicate that the amount of food available can influence inter-sexual variation in body size within a vertebrate species. Sex-specific developmental plasticity may be favored if it allows individuals to take advantage of varying levels of food opportunities offered by different habitats, by reducing competition between the sexes. As such, plasticity in response to food availability may have played a role in the invasion success of A. sagrei. This study adds to our growing understanding of the effect of resource availability in shaping SSD in reptiles and lends further support to the condition-dependence hypothesis, according to which the larger sex should display greater plasticity in growth in response to environmental conditions

Field courses narrow demographic achievement gaps in ecology and evolutionary biology.

Disparities remain in the representation of marginalized students in STEM. Classroom-based experiential learning opportunities can increase student confidence and academic success; however, the effectiveness of extending learning to outdoor settings is unknown. Our objectives were to examine (a) demographic gaps in ecology and evolutionary biology (EEB) major completion, college graduation, and GPAs for students who did and did not enroll in field courses, (b) whether under-represented demographic groups were less likely to enroll in field courses, and (c) whether under-represented demographic groups were more likely to feel increased competency in science-related tasks (hereafter, self-efficacy) after participating in field courses. We compared the relationships among academic success measures and demographic data (race/ethnicity, socioeconomic status, first-generation, and gender) for UC Santa Cruz undergraduate students admitted between 2008 and 2019 who participated in field courses (N = 941 students) and who did not (N = 28,215 students). Additionally, we administered longitudinal surveys to evaluate self-efficacy gains during field-based versus classroom-based courses (N = 570 students). We found no differences in the proportion of students matriculating at the university as undecided, proposed EEB, or proposed other majors across demographic groups. However, five years later, under-represented students were significantly less likely to graduate with EEB degrees, indicating retention rather than recruitment drives disparities in representation. This retention gap is partly due to a lower rate of college completion and partly through attrition to other majors. Although under-represented students were less likely to enroll in field courses, field courses were associated with higher self-efficacy gains, higher college graduation rates, higher EEB major retention, and higher GPAs at graduation. All demographic groups experienced significant increases in self-efficacy during field-based but not lecture-based courses. Together, our findings suggest that increasing the number of field courses and actively facilitating access to students from under-represented groups can be a powerful tool for increasing STEM diversity

Field and laboratory measurements of SVL in male and female A. sagrei

Field and laboratory measurements of snout-vent length (SVL) of male and female A. sagrei lizards. Field data: Adult males and adult females were captured on six Bahamian islands (Acklins, Andros, Grand Bahamas, Chub Cay, Pidgeon Cay and Staniel Cay). Laboratory data: feeding experiments of juvenile male and female A. sagrei raised under low or high food diets