A New Species of Rhagovelia and First Member of the Robusta Group Known From Mexico (Heteroptera: Veliidae)

Escalation and constraints of antagonistic armaments in water striders

“…Sexual dimorphism in the water strider genus Rhagovelia ranges from subtle to spectacular differences in morphology between the sexes (Figure 1A-D’). Rhagovelia populations contain both winged and wingless morphs (17, 18). In both male morphs, the foreleg tarsi are equipped with prominent, hook-like, combs that are absent in the females (Figure 1 E and E’).…”

“…narrow abdomen and pronotum projection) in only in two species from a single clade in our sample. These are Rhagovelia antilleana and Rhagovelia obesa both belonging to the collaris complex (18). The presence of modified females in this group, with the pronotum projection in winged females and narrow abdomen in wingless females (18), suggests that sexual antagonism had strongly impacted the evolution of the genus.…”

“…Waters striders have been widely used as a model to study sexual dimorphism and antagonistic co-evolution (7, 8, 15). Sexual dimorphism is particularly dramatic in the tropical genus Rhagovelia (Insecta, Gerromorpha, Heteroptera) (16–18), where both sexes often bear morphological traits reminiscent to those found in species with strong sexual conflict (1, 16–18). However, the process of sexual selection driving sexual dimorphism in Rhagovelia is unknown (1, 19).…”

“…However, the process of sexual selection driving sexual dimorphism in Rhagovelia is unknown (1, 19). Here, through morphological and behavioral quantifications, we identified a large set of potentially sexually antagonistic armaments in the Rhagovelia genus and tested their role during sexual interactions in a representative species called Rhagovelia antilleana (16–18). We then tested how variation in sexually antagonistic traits affects male and female success during sexual interactions.…”

Hox genes mediate the escalation of sexually antagonistic traits in water striders

“…However, whether pleiotropic developmental genes can mediate the opposing escalation in antagonistic traits in both sexes have not yet been tested. Because Hox genes establish the identity of the segments along the body axis, we tested the role of two of these genes in the escalation of sexually antagonistic traits consisting of various sex-specific morphological modifications in a water strider species called Rhagovelia antilleana (Andersen, 1982; Crumiere et al, 2018; Moreira & Ribeiro, 2009; Polhemus, 1997). By inactivating Sex Combs Reduced ( Scr ) and Ultrabithorax ( Ubx ) during nymphal instars, we uncovered the importance of these two genes in shaping both male and female antagonistic traits.…”