Search

The preference–performance hypothesis states that female insects oviposit on plants that result in optimal larval development. The objective of the present study was to evaluate the use of host plants of the genus Solanum by female butterflies of Mechanitis polymnia casabranca Haensch (Lepidoptera: Nymphalidae) and the performance of larvae reared on different species of Solanum. We performed field observations and oviposition experiments to evaluate the use of host plants. In the field, we recorded the abundance of host plants of the species Solanum robustum H. Wendl, Solanum mauritianum Scop., Solanum scuticum M. Nee, and Solanum paniculatum L. with and without oviposition by M. polymnia. In the oviposition experiment, we grew host plants representing common species in the field (S. mauritianum, S. robustum, and S. scuticum) in pots, with one plant per pot, which were then grouped in blocks of three plants, one of each species (n = 10 blocks). In the larval performance experiment, we reared larvae on leaves of one of three Solanum species and maintained them under controlled temperature and photoperiod conditions. We recorded the survival, larval development time, adult wing size, dry weight, and larval digestibility indices. In the field, females oviposited more frequently on S. robustum despite the greater abundance of S. mauritianum. In general, larvae reared on S. robustum or S. scuticum had highest larval performance. Larval mortality was higher in larvae reared on S. mauritianum (40.9%), followed by larvae reared on S. scuticum (7.5%) and S. robustum (6.8%). The adult wing size and dry weight were the highest in males and females originating from larvae reared on S. robustum. The results suggested a positive relationship between oviposition preference and larval performance in M. polymnia casabranca. [ABSTRACT FROM AUTHOR]

In this study, the host-plant range of Onciderini beetles was investigated during 4 years in an Atlantic rainforest of southeastern Brazil. Twelve species of Onciderini beetles girdled thirty-six plant species in the study site. In total, 1046 plants were girdled by Onciderini beetles as follows: 44.6% were Vochysiaceae, 15% were Mymosaceae, 12% were Melastomataceae, 9% were Lauraceae, 4% were Anacardiaceae and 15% were distributed among Meliaceae, Euphorbiaceae, Bombacaceae, Fabaceae, Thymelaeaceae, Cecropiaceae, Myrtaceae, Lecythidaceae, and Myrsinaceae. Onciderini beetles did not select hosts randomly. Most of the associations (70%) with host plants were caused by polyphagous beetles and different plant families showed different ratios of polyphagous, oligophagous and monophagous Onciderini in the study site. [ABSTRACT FROM AUTHOR]

Habitat selection by spiders may be strongly influenced by biotic, climatic, and physical factors. However, it has been shown that the selection of habitats by generalist predators (like spiders) is regulated more by the physical structure of the habitat than by prey availability. Yet, the preferences of spiders in relation to plants or plant traits remain poorly explored. In a remnant of the Atlantic forest in Brazil, the spider Selenops cocheleti is frequently detected on the trunks of plants from the Myrtaceae family. Here, we investigated quantitatively and experimentally whether the colonization of trees by S. cocheleti is related to plant species or the presence of specific structures on trunks. We found that S. cocheleti preferentially occurred on plants of the family Myrtaceae. This spider was also strongly associated with trees that have smooth trunks and/or exfoliating bark. Non-Myrtaceae plants that were occupied by this species have exfoliating bark (e.g., Piptadenia gonoacantha ) or deep fissures on the trunk (e.g., the exotic species Pinus elliottii ). Our results indicate that the selection of host plants by S. cocheleti is not species-specific, but based on the structural characteristics of plants. Trunks with exfoliating bark may benefit spiders by providing shelter against predators and harsh climatic conditions. Smooth surfaces might allow rapid movements, facilitating both attacks on preys and escape from predators. Our study emphasizes the importance of the physical structure of the habitat on spider's distribution. Future studies investigating how specific plant characteristics influence prey acquisition and predator avoidance would improve our understanding of habitat selection by these animals. [ABSTRACT FROM AUTHOR]