Light Patterns as Cues for Mate Choice in the Lekking White-Throated Manakin (Corapipo gutturalis)

--We explored in an exploded lek species the relationships between three alternatives hypotheses for typical skewed male mating success: (1) female preference for display-site characteristics; (2) female preference for male phenotypic traits; and (3) mate choice determined by the outcome of male dominance interactions. The possible role of these mechanisms of female choice was examined in the White-throated Manakin (Corapipo gutturalis), a species in which males display on the top of mossy fallen logs lying on the primary forest floor. Data on light intensity at the display site, lek attendance, male calling and display rates, visits by males and females, and mating success were collected on six males at a single lek. The two males with the brightest two arenas received high rates of female visitation and performed 71% of the mating attempts. However, only one of them successfully copulated because the other male was always disrupted by visiting males. The results suggest that light properties of the display site and attendance of the male determine the attractiveness of male display to females, whereas male interactions subsequently mediate copulatory success. Brightness of the display site appears as the primary cue for mate choice in C. gutturalis, but this is not used by females as an indicator of the males' relative dominance because the dominance status of males is not correlated with the brightness of their display sites. Received 23 April 1993, accepted 19 August 1993. IN LEK MATING SYSTEMS, males aggregate and display to attract females rather than defend females directly or monopolize resources females need. Females visit males only for mating and appear fairly free to choose among potential mates (Bradbury 1981, Bradbury and Gibson 1983). The high mating skew typical of lek species (Bradbury and Gibson 1983, Bradbury et al. 1985) argues for strong and convergent choice by females for certain male or site characteristics. Three alternative hypotheses have been suggested to explain these female preferences: male phenotype, display-site characteristics, and female copying (reviews in Bradbury and Gibson 1983, Balmford 1991). These hypotheses have been tested only at "classical eks" (Bradbury 1977, 1981) or "true leks" (Oring 1982), where males are densely clustered within sight of each other. In this paper, we explore the relationships of territory characteristics, male behavioral characteristics, and female visit rates at an "exploded lek" (Snow 1970, Bradbury 1981, Foster 1983). This pattern of males spacing, also called "quasi-lek" (Oring 1982) or "court" system (Beehler and Foster 1988), shows loosely clumped display sites that are not within sight of each other. To explain female preference in dispersed courts pecies, Borgia (1979) proposed the dominance-indicator model, which combines either female site preferences and/or phenotypic-trait preferences with male dominance. In the Neotropical manakins (Pipridae), lek mating is the rule and species how a large range of clustering from classical leks to exploded leks. As predicted by the hotspot model of lek evolution (Bradbury et al. 1986), variation in male clustering is correlated with female home-range size among syrupattic manakin species, but habitat preferences or attractiveness of certain males may be invoked to explain specific lek siting (Th•ry 1992). Despite intensive research conducted by Lill (1974a, b, 1976) in Trinidad, no behavioral or morphological cues for female choice are known for any of six syrupattic lekking manakins of French Guiana. In the Whitebearded Manakin (Manacus manacus), experimental studies in which top-ranking males were removed showed no shift in the spatial distribution of female visits and mating, suggesting female preference for display location (Lill 1974a). In M. manacus and the Golden-headed Manakin (Pipra erythrocephala), Lill (1974a, b,