A further new species for the genus Ananteris Thorell, 1891 (Scorpiones: Ananteridae) from a poorly prospected region of Brazilian Amazonia

Posted by
  A further new species for the genus Ananteris Thorell, 1891 (Scorpiones: Ananteridae) from a poorly prospected region of Brazilian Amazonia Abstract  A new species of the genus Ananteris Thorell, 1891 is described from the region which today defines the ‘Reserva Biológica do Río Trombetas’ in the state of Pará, Brazil. The collection of the unique specimen, presently study, took place previously to the definition of this reserve, in a joint field trip with a team of the Instituto Brasileiro de Desenvolvimento Florestal (IBDF). Ananteris antoni sp. n. is described based on one female specimen collected in a zone of dense humid forest, under death log. With this new description, the number of Ananteris species known for the scorpion fauna of Brazil is now raised to 33. Lourenço W. R., 2026. – A further new species for the genus Ananteris Thorell, 1891 (Scorpiones: Ananteridae) from a poorly prospected region of Brazilian Amazonia. Faunitaxys, 14(63): 1 – 5.  https://doi.o...

Background contrast affects detection and recognition of courting wolf spiders by intended and unintended receivers

Posted by

 


Background contrast affects detection and recognition of courting wolf spiders by intended and unintended receivers

Abstract

We used video playback of courting male Schizocosa ocreata wolf spiders to examine responses of intended receivers (conspecific females) and eavesdroppers (competitor males, predatory spiders, toads) to manipulations of spider color (natural color, monochromatic gray, monochromatic RBG average) displayed against complex leaf litter backgrounds (color, grayscale). Models of chromatic and achromatic contrast between spider stimuli and backgrounds were used to predict receiver responses. The results support the hypothesis that interactions between spider and background coloration affect detection and recognition, although responses varied with receiver type. Detection responses of intended receivers (female S. ocreata) did not fit predictions of the chromatic contrast model in some cases, but showed a fair fit to the achromatic model. Detection responses of social eavesdroppers (male S. ocreata) fit the chromatic and achromatic contrast models slightly better than did female responses (poor fit and very good fit, respectively). Eavesdropping wolf spider predators (Rabidosa) exhibited detection responses that significantly matched predictions of the chromatic (very good fit) and achromatic (excellent fit) models. Whereas jumping spiders (Phidippus) showed a good fit to the chromatic and achromatic contrast models, toad predators had a good fit only to the chromatic model. Recognition responses revealed a different pattern of fit to the chromatic and achromatic models across receiver types, although Rabidosa again indicated a significant fit to both models. Taken together, the results of this study identify both chromatic and achromatic features of spider appearance as likely explanations for differences in behavioral responses of intended and unintended receivers. This outcome suggests the possibility that both sexual and natural selection likely target different features of male appearance during courtship.

Uetz, G.W., Gilbert, R., Wilson, R. et al. Background contrast affects detection and recognition of courting wolf spiders by intended and unintended receivers. Behav Ecol Sociobiol 78, 43 (2024). https://doi.org/10.1007/s00265-024-03453-8