Site fidelity,size, and spatial arrangement of daytime home range of thumbprint emperor <Emphasis Type="Italic">Lethrinus harak</Emphasis> (Lethrinidae)

Although emperors (Lethrinidae) are commercially important fisheries resources in tropical and subtropical waters, their home range size and its spatial arrangement have not been sufficiently clarified. In the present study, the size and spatial arrangement of the daytime home range of the thumbprint emperor Lethrinus harak were investigated by using a portable GPS receiver. In a 150 m × 200 m quadrat, 21 individuals of the species were identified by their color pattern, and individuals were divided into four arbitrary size classes (class 1 < 20 cm TL ≤ class 2 < 25 cm TL ≤ class 3 < 30 cm TL ≤ class 4). Fish tracking by snorkeling was conducted with the portable GPS receiver. Daytime site fidelity of this species was high and there was a significant positive correlation between the home range size and fish total length. Home ranges of same-sized individuals abutted each other (20.3% area overlap), whereas those of different-sized individuals overlapped (48.3% area overlap). Agonistic behavior (attacking) occurred significantly more frequently between same-sized individuals than between different-sized individuals. These results suggest that daytime home ranges of Lethrinus harak can be regarded as territories against same-sized individuals, but not different-sized individuals.     

Detection of Bemisia tabaci Mediterranean cryptic species on soybean in São Paulo and Paraná States (Brazil) and interaction of cowpea mild mottle virus with whiteflies

Since the detection of Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) species in Brazil in the early 1990s, this whitefly has been the predominant species and the main viral vector in the country. In this work, whiteflies were collected from commercial soybean fields near and far from greenhouses where Mediterranean (MED) species had previously been detected infesting vegetable crops. Results indicated that MEAM1 was the predominant whitefly species in soybean in most sampling sites, while MED was found colonizing soybean plants in open field conditions alone and/or with MEAM1 in several places. Among the tested insects, MED species was mostly detected harbouring the facultative endosymbiont Hamiltonella. We also detected cowpea mild mottle virus (CPMMV) infecting soybean plants. Transmission assays demonstrated that MED species was more efficient transmitting CPMMV from beans to beans and from soybean to soybean plants than MEAM1, while MEAM1 was more efficient in transmitting the virus from soybean to bean than MED. Performance assays indicated that adult emergence of both species on CPMMV-infected soybean plants was higher when compared with the emergence on healthy plants. Moreover, nonviruliferous MED and MEAM1 adults preferred to settle more often on healthy plants, while viruliferous adults settled more often on CPMMV-infected soybean plants. As MED has already been found in soybean open fields in São Paulo and Paraná States, Brazil, and it is a good vector of CPMMV, we anticipate problems related to whitefly management and to increase in the incidence of the virus in soybean.