Entomologia Experimentalis et Applicata最新文献

The impacts of land-use change on biodiversity may be studied through different approaches and biological scales, being abundance and morphological traits two trustworthy variables that can depict a cause-and-consequence scenario of environmental transformations at the population scale. In the tropics, native non-forested ecosystems structure complex ecological communities, with species presenting complex responses toward environmental shifts. We investigated the effects of land-use change on the abundance and morphological traits of dung beetle species in one of the major Neotropical wetlands, the Brazilian Pantanal. To achieve this, we sampled individuals of two widely distributed South American dung beetle species, Dichotomius bos and Dichotomius nisus, across native grasslands, exotic pastures, and soybean fields. We measured individuals' body mass, pronotum length/width ratio, relative protibial size, elytra length/width ratio, and size of pronotum relative to abdomen size—which are directly linked to ecosystem functions provided by dung beetles. Exotic pastures and soybean croplands had a higher abundance of dung beetles than native grasslands. Furthermore, soybean croplands had individuals with a lower pronotum length/width ratio than in native grasslands and exotic pastures for both species studied. Morphological traits in D. nisus were more strongly influenced by land-use change than those in D. bos, indicating that even closely related species may respond differently to habitat alterations due to different ecological adaptations. Finally, these findings highlight that morphological traits are sensitive to land-use changes in non-forested ecosystems and could be important to complement the information obtained from studies that used community metrics.

Effective cumulative temperature and developmental zero point are important indicators for estimating the timing of organism development and the area of distribution. These indicators are generally considered to have unique values for different species of organisms and are also important for predicting the distribution range of animals and plants, especially insect pests. These values generally are species-specific, but there is variation within populations in traits having a genetic component. However, there are no studies on what kind of selection pressure affects these indicator values. To address this issue, it would be worthwhile to compare these values using individuals of strains that have been artificially selected for life-history traits by rearing them at various temperatures and calculating these indicators from developmental days and temperatures. In the present study, eggs were taken from adults of strains with many generations of artificial selection on two life-history traits (age at reproduction and developmental period) of the melon fly, Zeugodacus cucurbitae, under constant temperature conditions. Eggs were reared at five different temperatures, and the effective cumulative temperatures and developmental zero points of the larval and developmental periods were compared. The results demonstrate that artificial selection on life-history traits in Z. cucurbitae induces evolutionary changes in both the effective cumulative temperature and the developmental zero point across successive generations.

Matching the provenance of potential biological control agents with that of the invasive weed population is often considered crucial for biological control success, as it is argued that natural enemies from the same provenance will have local adaptations that make them more damaging to the weed than natural enemies from elsewhere. However, few studies have directly tested the importance of provenance matching. In this study, we conducted host testing to compare the fecundity and damage caused by Calomela intemerata Lea (Coleoptera: Chrysomelidae) beetles on Acacia auriculiformis A. Cunn ex Benth. (Fabaceae) plants from different provenances. Calomela intemerata beetles from Queensland laid more eggs on the growing tips of plants from Queensland than on plants from other provenances. Likewise, adult beetles from Queensland caused significantly more damage to the growing tips of plants from Queensland than to plants from elsewhere. However, we observed some idiosyncratic results, and beetles laid significantly more eggs on non-plant substrates than on the plants themselves, indicating more research is required to understand the oviposition behaviour of these beetles. Although our results support the idea that provenance matching may be important for these beetles, additional work is needed to understand the general significance of provenance matching in biological control.

Initial population size and resource availability are key drivers of population dynamics. However, the synergistic effects of initial population size and resource availability on intrinsic growth rates remain poorly understood. We conducted an experiment using maize weevils (Sitophilus zeamais Boisduval 1835; Coleoptera: Curculionidae) to disentangle the effects of these two factors on intrinsic growth rates. We simulated closed populations with initial sizes of 8, 16, and 32 individuals, while varying resource availability (maize seeds) proportionally: 70 g for 8 individuals, 140 g for 16 individuals, and 280 g for 32 individuals. Growth models were fitted for each population, and the estimated intrinsic growth rate served as the response variable to assess the effects of initial population size and resource availability. Statistical analyses included ANOVA, variance partitioning, and linear regression. Both initial population size and resource availability negatively affected intrinsic growth rates, with no significant interaction between them. We propose that initial population size intensifies density dependence, whereas resource availability acts as a mate-finding barrier. Our findings highlight an additional critical driver of population dynamics, the barrier effect, beyond the conventional factors of initial population size and resource availability.

Flight intercept traps are important tools for the monitoring and surveillance of forest Coleoptera. Although collection cup effects on the abundance of target taxa are well-documented, these effects remain poorly understood. Here, we investigated the comparative efficacy of three wet (saturated saltwater, propylene glycol, and soapy water) and one dry (dichlorvos strip) collection cup treatments on the capture of forest insects. We observed significant differences in capture rates across treatments, with wet cups generally resulting in higher captures of phytophagous and predatory taxa. Dry cups captured the largest quantities of carrion-associated taxa. These findings challenge the prevailing hypothesis of insect escape from dry collection cups and suggest that olfactory stimuli associated with collection cups are important in mediating trap performance. Despite these insights, the specific mechanisms driving these preferences remain unknown and should be the focus of future research.

Rice root aphids (RRAs), Rhopalosiphum rufiabdominale (Sasaki) (Hemiptera: Aphididae), reportedly feed on a wide range of monocotyledonous plants (“monocots”) and dicotyledonous plants (“dicots”). However, possible preference for either monocots or dicots, as well as the mechanisms underlying host plant selection, have not yet been investigated. In two-choice and no-choice laboratory experiments, we tested whether RRAs (1) select monocots or dicots as host plants, (2) multiply faster on monocots or dicots, and (3) choose preferred host plants based solely on olfactory cues. When RRAs were offered a choice between two potted monocots (rye vs. barley), they showed no preference, but when they were offered a choice between rye and a dicot (cannabis, celery, coriander, lettuce, pepper, squash, tomato, or marigold), they invariably selected and multiplied faster on rye. Similarly, in a no-choice experiment, where RRAs were confined in a mesh bag fitted with a single host plant, they multiplied equally well on monocots (rye and barley), but significantly less on any of the eight dicots. In moving-air two-choice Y-tube olfactometer bioassays, which presented olfactory but not visual cues of monocots and dicots, the first- and final choices of RRAs were mostly indifferent, suggesting that RRAs locate their preferred monocots based not solely on plant odor. As RRAs are emerging pests in commercial cannabis and vegetable production, it is conceivable to use rye as a trap crop to divert RRAs from valuable cannabis and vegetable crops. This concept, however, still requires testing in commercial crop production settings.