Search

Deinopidae spiders are known mainly for their web-building behavior and prey-capture strategy. However, studies on their population ecology are scarce. Therefore, we evaluated the population fluctuation, phenology, and diet of Deinopis cf. cylindracea. We also investigated how abiotic (precipitation and temperature) and biotic (prey availability) factors influence the abundance of this species. Our results showed that D. cf. cylindracea has an annual cycle with a maximum density in March. The reproduction cycle occurs from March to July. The recruitment of spiders occurred between July and October, followed by a peak of young individuals in December, juveniles in February, subadults in April, and adults in May, indicating a 'fall stenochronous' phenological pattern. The climatic variables were important factors that influenced the fluctuation of the age of D. cf. cylindracea. Although we did not find a positive correlation between the climate and its abundance at time 0, we did observe a correlation with a delay of three months. The main preys were Formicidae and Coleoptera, and not all available preys were part of the spiders' diet. These results indicate that the spiders require time to respond to changes in environmental conditions and provide information about the different stages of development over time. [ABSTRACT FROM AUTHOR]

Over a two-year period, we conducted population studies ofSelenops cocheletiinhabiting trunks ofPlinia cauliflora(Myrtaceae) andPinus elliottii(Pinaceae) in southeastern Brazil. Adult females were present year-round while adult males were only present during summer, indicating a “stenochronous summer” phenological pattern. The longevity of adult females enables them to continuously generate egg-sacs throughout the year, resulting in the permanent recruitment of individuals. In conclusion, this study provides new insights into the life-history ofS. cocheletiand how climatic variables and prey abundance influence the population abundance of the different age classes and adult sexes. [ABSTRACT FROM AUTHOR]

Parental care may present an important role in the survival of waterfowl against natural enemies. Here, we provide a detailed description of the parental response of a pair of White-faced Whistling-ducks (Dendrocygna viduata, Anatidae) after an attack of a duckling by the carnivorous fishHoplias malabaricus(Characidae). Despite the successful rescue of the duckling by the parents, there appeared to be a trade-off between reintegrating the injured duckling into the group and saving the rest of the chicks. [ABSTRACT FROM AUTHOR]

Copyright of Studies on Neotropical Fauna & Environment is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Beetles in the genus Oncideres (Cerambycidae: Lamiinae) are girdlers and borers that can cause plant mortality and alterations in the recruitment and age structure of their host‐plant populations. Host‐plant association, oviposition behavior, development and insect associates of Oncideres humeralis were studied in southeastern Brazil. Oncideres humeralis Thorms used four species of Melastomataceae as host plants. Females oviposited in forks of branches and their larvae fed on the parenchyma tissue of the forks. Histological analyses showed that these sites were the softest parts of the branches and provided an entrance for newly hatched larvae. Females prepared their oviposition sites with their mandibles, and inserted their ovipositors into the slits to deposit one to three eggs under the bark. We found about six oviposition slits per branch and a mean of eight eggs per branch. The larvae bored into and grew inside the girdled branches. Larval development took 10–12 months. Another cerambycid, Temnopsis megacephala Germ, developed in the thinner sections of branches that had been girdled by O. humeralis and was thus considered a secondary colonizer.ResumoBesouros do gênero Oncideres (Cerambycidae: Lamiinae) são serradores a brocadores e podem provocar mortalidade de plantas, alterações no recrutamento e na estrutura estária de populações de plantas hospedeiras. Associação com plantas hospedeiras, comportamento de oviposição, desenvolvimento e insetos associados a Oncideres humeralis foram estudados na Sudeste do Brasil. Fêmeas colocaram ovos nas bifurcações dos ramos e suas larvas alimentaram‐se do parênquima da forquilha do ramo. Análises histológicas mostraram que este local é a região mais mole da forquilha do ramo e proporciona uma porta de entrada para larvas de primeiro estágio. Fêmeas prepararam estes locais de oviposição com suas mandíbulas e inseriram seus ovipositores dentro da fenda para depositar de um a três ovos sob a casca. Encontramos cerca de seis sítios de oviposição e média de oito ovos por ramo. As larvas brocaram o interior e se desenvolveram dentro dos ramos serrados. O desenvolvimento larval requereu de 10 a 12 meses. O. humeralis Thorms. usaram quatro espécies de Melastomataceae como plantas hospedeiras. Outro cerambicídeo, Temnopsis megacephala Germ. desenvolveram em ramos mais finos não colonizados por O. humeralis, e foi considerado um colonizador secundário. [ABSTRACT FROM AUTHOR]