Roland, A.-B. | bioRxiv Science

bioRxiv2024

Does Haldane's rule speciation within mimetic Poison frogs?

To explain how populations with distinct warning signals coexist in close parapatry, we experimentally assessed intrinsic mechanisms acting as reproductive barriers within three Ranitomeya poison-frog species. For all species, assortative mating did not occur, nor did a survival disadvantage for inter-population hybrids. However, in Ranitomeya fantastica, these hybrids of the male sex are sterile, an outcome predicted by Haldanes rule. Our results suggest a possible XY sex determinism in R. fantastica, and show that this process is associated with an extraordinary diversity, leading to speciation. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/586569v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@9cd116org.highwire.dtl.DTLVardef@16303dforg.highwire.dtl.DTLVardef@19339acorg.highwire.dtl.DTLVardef@af7718_HPS_FORMAT_FIGEXP M_FIG C_FIG

evolutionary biology↗

bioRxiv2022

Contrasting parental roles shape sex differences in poison frog space use but not navigational performance

Sex differences in vertebrate spatial abilities are typically interpreted under the adaptive specialization hypothesis, which posits that male reproductive success is linked to larger home ranges and better navigational skills. The androgen spillover hypothesis counters that enhanced male spatial performance may be a byproduct of higher androgen levels. Animal groups that include species where females are expected to outperform males based on life-history traits are key for disentangling these hypotheses. We investigated the association between sex differences in reproductive strategies, spatial behavior, and androgen levels in three species of poison frogs. We tracked individuals in natural environments to show that contrasting parental sex roles shape sex differences in space use, where the sex performing parental duties shows wider-ranging movements. We then translocated frogs from their home areas to test their navigational performance and found that the caring sex outperformed the non-caring sex only in one out of three species. In addition, males across species displayed more explorative behavior than females. Furthermore, androgen levels correlated with explorative behavior and homing accuracy. Our findings suggest that poison frog reproductive strategies shape space use patterns but not navigational performance, providing counterevidence to the prevailing view of adaptive sex differences in spatial abilities.

animal behavior and cognition↗