Female Choice in the Synchronously Waving Fiddler CrabUca annulipes

Abstract

In the fiddler crab, Uca annulipes, males attract receptive females into their burrows by waving their greatly enlarged major claw. We have previously shown that males clustered around a female wave in close synchrony. Females may have a preference for leading signals and synchronised waving may arise as an epiphenomenon of competition between males to signal first. Indeed, the males in clusters that females approach and visit in their burrows are more likely to produce leading waves than are their neighbours. Here we document two other differences in the waving behaviour of visited males and their neighbours. First, visited males complete the downward component of the wave more rapidly than their neighbours. Second, the interval between the end of one wave and the start of the next is shorter for visited males. How can waving be synchronous if visited males wave faster than their neighbours? While only 9% (40/431) of waves by neighbours did not overlap those of the visited male, 22% (110/501) of visited male waves did not overlap the wave of a focal neighbour (111 visited male‐neighbour dyads). Hence, while overlapping waves are nearly synchronous, visited males produce additional, ‘nonoverlapping’ waves that result in a higher wave rate than that of their neighbours.

Enigmatic ornamentation eases male reliance on courtship performance for mating success

“…In addition, above the threshold, as courtship rate increased, a male's likelihood of copulating increased. Female preferences for male courtship rate have been documented for a wide range of animals including, but not limited to, orthopterans, homopterans and anurans (reviewed in Gerhardt & Huber 2002), fiddler crabs (Backwell et al, 1999;Murai and Backwell, 2006), birds and mammals (reviewed in Byers et al 2010), and wolf spiders (Kotiaho et al, 1998a;Parri et al, 2002;Rypstra et al, 2003;Delaney et al, 2007;Gibson and Uetz, 2008;Lomborg and Toft, 2009;Shamble et al, 2009;Rundus et al, 2010). Thus, our findings that female choice depends upon courtship rate and that higher courtship rates result in faster copulations in S. stridulans were not unexpected.…”

“…Elaborate sexual ornaments often accompany complex movements during animal displays (Zuk et al, 1995;Backwell et al, 1999;Hebets and Uetz, 2000;Madsen et al, 2004;Loyau et al, 2005;Murai and Backwell, 2006), making it feasible for selection to act on interactions between display properties and ornament characteristics (Kodric-Brown and Nicoletto, 2001;Candolin, 2003;Hebets and Papaj, 2005;Smith et al, 2009). An example of such naturally selected interactions is in the garter snake, Thamnophis ordinoides, where it is the combination of antipredator behavior and color patterns that is under selection (Brodie 1992).…”

Alometria no crescimento de Uca mordax (Smith) (Crustacea, Decapoda, Ocypodidae) na Baía de Guaratuba, Paraná, Brasil

“…1). Embora o combate e a defesa do território, também, sejam funções executadas pelos machos utilizando a maior quela (CRANE 1975, BACKWELL et al 1999, MORIITO & WADA 2000, POPE 2000, YAMAGUCHI 2001, PRATT et al 2003, no caso de U. mordax do presente estudo, o significado biológico do tamanho avantajado da mesma deve estar relacionado com o aceno sexual ("waving") que é uma estratégia visual: o tamanho gigantesco da quela condicionaria um incremento na eficiência desta atividade mais do que vantagens em combates. Numa eventual luta, os animais provavelmente Outros Brachyura ocorrentes no litoral brasileiro, também, mostraram níveis de alometria mais baixos no crescimento da maior quela quando comparados com Uca.…”

Crescimento relativo e destreza dos quelípodos de Uca maracoani (Latreille) (Crustacea, Decapoda, Ocypodidae) no Baixio Mirim, Baía de Guaratuba, Paraná, Brasil

“…Esta enorme quela tem importante papel nos comportamentos agonísticos, de defesa de território e de corte nupcial (CRANE 1975, BACKWELL et al 1999, MORIITO & WADA 2000, POPE 2000, PRATT et al 2003. Devido a esta característica, estes animais foram objetos de estudos morfométricos em diversos países, a saber, Uca pugilator (Bosc, 1802) SANTOS et al (1995), Acanthonyx scutiformis (Dana, 1851) por HIYODO & FRANSOZO (1995), Goniopsis cruentata (Latreille, 1803) animais, mas, como o tegumento rígido dos Crustacea permite obter medidas acuradas, e as diferenças na forma do corpo associadas com o sexo e a puberdade são contrastantes, este grupo animal tem se tornado particularmente atraente para estudos alométricos (HARTNOLL 1974(HARTNOLL , 1978.…”