Does sexual conflict contribute to the evolution of novel warning patterns?

Why warning patterns are so diverse is an enduring evolutionary puzzle. Because predators associate particular patterns with unpleasant experiences, an individual's predation risk should decrease as the local density of its warning pattern increases, promoting pattern monomorphism. Distasteful Heliconius butterflies are known for their diversity of warning patterns. Here, we explore whether interlocus sexual conflict can contribute to their diversification. Male Heliconius use warning patterns as mating cues, but mated females may suffer costs if this leads to disturbance, favouring novel patterns. Using simulations, we show that under our model conditions drift alone is unlikely to cause pattern diversification, but that sexual conflict can assist such a process. We also find that genetic architecture influences the evolution of male preferences, which track changes in warning pattern due to sexual selection. When male attraction imposes costs on females, this affects the speed at which novel pattern alleles increase. In two experiments, females laid fewer eggs with males present. However, although males in one experiment showed less interest in females with manipulated patterns, we found no evidence that female colouration mitigates sex-specific costs. Overall, male attraction to conspecific warning patterns may impose an unrecognized cost on Heliconius females, but further work is required to determine this experimentally.

Light environment influences mating behaviours during the early stages of divergence in tropical butterflies.

Speciation is facilitated when traits under divergent selection also act as mating cues. Fluctuations in sensory conditions can alter signal perception independently of adaptation to the broader sensory environment, but how this fine-scale variation may constrain or promote behavioural isolation has received little attention. The warning patterns of Heliconius butterflies are under selection for aposematism and act as mating cues. Using computer vision, we extracted behavioural data from 1481 h of video footage, for 387 individuals. We show that the putative hybrid species H. heurippa and its close relative H. timareta linaresi differ in their response to divergent warning patterns, but that these differences are strengthened with increased local illuminance. Trials with live individuals reveal low-level assortative mating that is sufficiently explained by differences in visual attraction. Finally, results from hybrid butterflies are consistent with linkage between a major warning pattern gene and the corresponding behaviour, though the differences in behaviour we observe are unlikely to cause rapid reproductive isolation as predicted under a model of hybrid trait speciation. Overall, our results reveal that the contribution of ecological mating cues to reproductive isolation may depend on the immediate sensory conditions during which they are displayed to conspecifics.

Absence of visual cues motivates desert ants to build their own landmarks.

The desert ants Cataglyphis fortis inhabit the harsh salt pans of Tunisia. The individually foraging ants rely on path integration to navigate back to their nest.1,2,3,4 However, as path integration accumulates errors5 at a rate that increases with distance traveled,6,7 it is supplemented by visual and olfactory cues.8,9,10,11,12,13 We show that despite their impressive homing accuracy, ants returning from long foraging journeys face a mortality rate of up to 20%. To facilitate homing, colonies inhabiting the featureless center of the salt pan build tall nest hills as visual cues. Removing these hills triggers rebuilding, but visual artificial landmarks placed near the nest entrance are sufficient to suppress the ants' rebuilding activity. Our data suggest that the desert ant builds its own landmark on purpose in a featureless environment to increase its chances of successful homing and survival. VIDEO ABSTRACT.

Significações de jogo: um estudo com professores de Educação Física / Meanings of play: a study with school-level Physical Education teachers / Significaciones del juego: un estudio con profesores escolares de Educación Física

Este trabalho investigou as significações de jogo constituídas pelos professores de Educação Física que atuam nas primeiras séries do ensino fundamental. Utilizou-se a entrevista semiestruturada para analisar: a função do trabalho com o jogo; as significações procedentes de professores de outras áreas e da equipe gestora sobre o trabalho com o jogo e; as condições de trabalho com o jogo. Os resultados revelaram: a tensão entre o competir/cooperar, a desvalorização do futebol e a busca pela ressignificação; a valorização sobre a necessidade de trabalhar a leitura e a escrita, as capacidades físicas e o futebol; sendo que os maiores incômodos encontram-se centrados no objetivo a ser alcançado e no "como", ao invés de "por quê". Concluiu-se que o trabalho com o jogo vive um processo de busca de valorização e ressignificação da sua função, o que reitera a necessidade desse olhar historicizado para o sujeito que constitui a Educação Física escolar.

This paper investigated the meanings imbued by Physical Education teachers upon play activities with their students from the first primary education classes. We have employed semi-structured interview in order to analyze: the function of play within their work; the meanings coming from teachers of other disciplines and the administrative team about this work with play; and the conditions of the work with play. The results revealed: a tension between competing and cooperating, the devaluing of soccer and a search to re-signification; the valuing of the need to work on reading and writing; physical abilities and soccer; and the central issues are around the final goal of play and the "how" instead of "why". We have reached the conclusion that work with play is going through a process of search for value and re-signification of its function, which reiterates the need for this historical approach for the subject that constitutes school-level Physical Education.

Este trabajo investigó las significaciones de juego constituidas por los profesores de Educación Física actuantes en los primeros grados de la escuela primaria. Se utilizaron entrevistas semiestructuradas para analizar: la función del trabajo con juegos; los significados provenientes de profesores de otras áreas y el equipo de gestión sobre el trabajo con juegos y; las condiciones de trabajo con juegos. Los resultados revelaron: la tensión entre competir/cooperar, la desvalorización del fútbol y la búsqueda de su resignificación; la valorización de la necesidad de trabajar con lecto-escritura, las capacidades físicas y el fútbol; siendo que las mayores dificultades se encuentran alrededor del objetivo a alcanzar y en el "cómo", en vez del "por qué". Se concluyó que el trabajo con juegos pasa por un proceso de búsqueda de una valorización y resignificación de su función, lo que reitera la necesidad de esta mirada histórica del sujeto constituido por la Educación Física escolar.