The role of body size and cuticular hydrocarbons in the desiccation resistance of invasive Argentine ants (Linepithema humile).

An insect's cuticle is typically covered in a layer of wax prominently featuring various hydrocarbons involved in desiccation resistance and chemical communication. In Argentine ants (Linepithema humile), cuticular hydrocarbons (CHCs) communicate colony identity, but also provide waterproofing necessary to survive dry conditions. Theory suggests different CHC compound classes have functional trade-offs, such that selection for compounds used in communication would compromise waterproofing, and vice versa. We sampled sites of invasive L. humile populations from across California to test whether CHC differences between them can explain differences in their desiccation survival. We hypothesized that CHCs whose abundance was correlated with environmental factors would determine survival during desiccation, but our regression analysis did not support this hypothesis. Interestingly, we found the abundance of most CHCs had a negative correlation with survival, regardless of compound class. We suggest that the CHC differences between L. humile nests in California are insufficient to explain their differential survival against desiccation, and that body mass is a better predictor of desiccation survival at this scale of comparison.

"OMG, Yes!": Feasibility, Acceptability, and Preliminary Efficacy of an Online Intervention for Female Sexual Pleasure.

The purpose of this study was to evaluate the acceptability, feasibility, and preliminary efficacy of using an online educational resource that presents research-informed strategies for women's pleasure, OMGyes.com, as a resource to empower women to broaden the ways in which they understand, advocate for, and enjoy sexual pleasure. A cohort of 870 adult women was given access to OMGyes.com and asked to explore the resource over a four-week period and complete online pre/post questionnaires. Participants reported a high level of satisfaction with the relatability, usefulness, and functionality of OMGyes.com. We observed statistically significant, large effect size increases in participants' knowledge about their own pleasure preferences, their confidence and positivity about that knowledge, as well as how pleasurable their sexual experiences were during both masturbation and partner sex. Many participants reported that after using OMGyes.com they felt more motivated to explore their preferences and more confident to explain their preferences to their partners. Our data suggest that OMGyes.com may be useful for positively impacting how women think about sexual pleasure, how they understand their own specific preferences, how they advocate for what they enjoy with partners, and how they actually experience pleasure.

Desiccation Resistance and Micro-Climate Adaptation: Cuticular Hydrocarbon Signatures of Different Argentine Ant Supercolonies Across California.

Cuticular hydrocarbons (CHCs), the dominant fraction of the insects' epicuticle and the primary barrier to desiccation, form the basis for a wide range of chemical signaling systems. In eusocial insects, CHCs are key mediators of nestmate recognition, and colony identity appears to be maintained through a uniform CHC profile. In the unicolonial Argentine ant Linepithema humile, an unparalleled invasive expansion has led to vast supercolonies whose nestmates can still recognize each other across thousands of miles. CHC profiles are expected to display considerable variation as they adapt to fundamentally differing environmental conditions across the Argentine ant's expanded range, yet this variation would largely conflict with the vastly extended nestmate recognition based on CHC uniformity. To shed light on these seemingly contradictory selective pressures, we attempt to decipher which CHC classes enable adaptation to such a wide array of environmental conditions and contrast them with the overall CHC profile uniformity postulated to maintain nestmate recognition. n-Alkanes and n-alkenes showed the largest adaptability to environmental conditions most closely associated with desiccation, pointing at their function for water-proofing. Trimethyl alkanes, on the other hand, were reduced in environments associated with higher desiccation stress. However, CHC patterns correlated with environmental conditions were largely overriden when taking overall CHC variation across the expanded range of L. humile into account, resulting in conserved colony-specific CHC signatures. This delivers intriguing insights into the hierarchy of CHC functionality integrating both adaptation to a wide array of different climatic conditions and the maintenance of a universally accepted chemical profile.