Predação e parasitismo em sementes de duas populações de Parkia platycephala Benth., em áreas de cerrado no nordeste do Brasil

Abstract

-(Predation and parasitism on seeds of two populations of Parkia platycephala Benth., from "cerrado" areas in Northeast Brazil). Two morphologically distinct populations of Parkia platycephala with different densities in the Cerrado, have their seeds preyed by larvae of the coleoptera Acanthoscelides imitator Kingsolver 1985, which are parasitized by the hymenoptera Stenocorse bruchivora Crawford 1900. In this study the effects of nesting, predation, and parasitism on seed germination were evaluated, and the rates of these events were compared between the two populations. Germination tests were conducted in laboratory, using four replicates of 50 seeds. Nesting, predation and parasitism rates for each population were estimated by sampling seeds from 20 fruits per individual, and from 15 individuals per population. The seeds of P. platycephala exhibit dormancy enforced by the seed coat. The nesting breaks the dormancy, and the pre-dispersal predation of seeds by the coleoptera larvae make them inviables. The larvae predation is biologically controlled by the hymenoptera parasitism. The seed predation rates for each population were 28% and 12%, respectively, being significantly higher in the white population, which produces more and smaller seeds per fruit than the other population. The highest predation occurs because of the highest nesting rate by the coleopterans, which is positively correlated with the number of seeds per fruit. The parasitism rate was 8%, approximately, and was not significantly different between the populations. The results indicate that the differences between the densities of these populations were not related to the biological interactions, as seed predation and parasitism.Key words -"cerrado", germination, parasitism, Parkia platycephala, seed predation RESUMO -(Predação e parasitismo em sementes de duas populações de Parkia platycephala Benth., em áreas de cerrado no nordeste do Brasil). Duas populações morfologicamente distintas de Parkia platycephala, que diferem quanto à densidade no cerrado, têm suas sementes predadas por larvas de coleópteros Acanthoscelides imitator Kingsolver 1985 as quais são parasitadas por himenópteros Stenocorse bruchivora Crawford 1900. Neste trabalho determinou-se o efeito da nidificação, predação e parasitismo na germinação das sementes, comparando-se as taxas destes eventos entre as duas populações. Os testes de germinação foram conduzidos em laboratório, utilizando-se quatro repetições de 50 sementes. As taxas de nidificação, predação e parasitismo nas populações no cerrado foram estimadas em amostras de sementes colhidas de 20 frutos por indivíduo, em 15 indivíduos por população. As sementes de P. platycephala exibem dormência imposta pelo tegumento. A nidificação quebra a dormência e a predação pré-dispersão das sementes por larvas dos coleópteros as inviabiliza, sendo biologicamente controlada pelo parasitismo das larvas pelos himenópteros. A taxa de predação das sementes foi de 28% e 12% respectivamente, sendo significativamente maior na pop...

Pre-dispersal seed predation and abortion in species of Callisthene and Qualea (Vochysiaceae) in a Neotropical savanna

“…Studies comparing populations in terms of the occurrence of abortion and predation can further understanding of the ecological consequences to plant reproduction and persistence (Bradford & Smith 1977;Ehrlén 1996;Pizo 1997;Crawley 2000;García et al 2000García et al , 2001Steffan-Dewenter et al 2001;Leimu et al 2002;Baldissera & Ganade 2005;Marino et al 2005;Figueiredo et al 2008). In the Cerrado of Brazil, one of the most well-represented and characteristic families of woody plants is the Vochysiaceae, some species of which are among the most common and widespread in the Biome (Haridassan & Araújo 1988;Ratter et al 1996;Appolinário & Schiavini 2002;Lopes et al 2011).…”

Pre‐dispersal seed predators and fungi differ in their effect on Luehea seemannii capsule development, seed germination, and dormancy across two Panamanian forests

“…, Auld & Denham , De Figueiredo et al . , Raimúndez‐Urrutta , Pickering , Amri , Delerue et al . , Van Klinken & White ), but also include vertebrates such as monkeys (Peres , Agetsuma & Noma ), mice (Fedriani & Manzaneda ), and parrots (Renton , Bollen & Vanelsacker ).…”