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生物学
The reproductive biology of a Central American cichlid Neetroplus nematopus in Lake Xiloá ,Nicaragua
<正> This study was conducted to provide a five-year database on the breeding seasonality and breeding biology of a CentralAmerican cichlid fish Neetroplus nematopus, a biparental substratum-spawning cichlid that cares for its eggs, wrigglers, andfry for up to six weeks. A total of 503 breeding pairs were monitored for breeding success. Breeding pairs of N. nematopus aresexually dimorphic in size, with females averaging 39% of male body mass. Fry emerged from 85% of nesting cavities. Afterthree weeks, only 30% of the broods were present in the nesting cavity; these broods had a 30% survival rate, giving a 9% overallsurvival rate. Nineteen percent of the successful parents with three-week-old broods adopted foreign fry. A consistent unimodalbreeding peak in December was observed for five years. This breeding peak differed dramatically from the bimodal breedingseason 20 years found in the 1970s. The effects of extensive grenade fishing practices during the 1980s might have played a substantialrole in the observed change. Grenade fishing stopped in 1991, and the number of A. nematopus pairs increased by 136%from 1990 to 1995. With increased density of breeding fish, the breeding season for this species also expanded. The balance betweendivergent selection due to competition for breeding sites and stabilizing selection due to predation pressure on offspring islikely to mold the breeding season for N. nematopus and other cichlids of Lake Xiloá. We suggest that brood adoption and synchronyof breeding is a strategy to reduce predation on the parent's own young
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Current Zoology
2010年01期

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