Journal of Applied Entomology最新文献

In Argentina, only two insect species significantly damage urban palms: Coraliomela quadrimaculata (Coleoptera: Chrysomelidae) and Paysandisia archon (Lepidoptera: Castniidae), the latter having recently reached pest status in several European countries. This study analyses factors associated with palm trees and patches that influence the incidence of damage caused by these insects in a big city of central Argentina. Twenty-four palm groups were surveyed in the urban area, and variables were measured at two scales. At the patch scale: number of palm species, palm density, and distance to the city centre; at the palm scale: geographic origin of palm species, trunk diameter, palm height, number of fronds, and degree of isolation. Presence/absence of damage was analysed using multiple logistic regression models. The results revealed a higher prevalence of damage caused by C. quadrimaculata compared to P. archon, with a significant relationship between palm abundance and the proportion of damage for the former species. The damage by C. quadrimaculata increased with the number of fronds, while wider trunks made palms more susceptible to P. archon. Neotropical palm species were less affected by P. archon but more prone to C. quadrimaculata damage. Palms were more vulnerable to C. quadrimaculata in monospecific patches, whereas P. archon caused greater damage in denser and plurispecific patches. Urbanisation strongly influenced C. quadrimaculata damage but had no detectable effect on P. archon. Understanding the differing impacts of C. quadrimaculata and P. archon is essential for developing targeted management strategies. This is particularly urgent for C. quadrimaculata, whose population is increasing in Argentina. Further research is crucial to better understand the factors driving P. archon damage, given its high invasive potential and significant impact as an emerging pest.

As essential pollinators to native plant species, Bombus (Latreille) are integral components of terrestrial ecosystems. Canada is home to approximately 41 native bumblebee species, 24.4% of which are threatened with extinction globally. In cases of extreme population decline, ex situ conservation, including conservation breeding and reintroduction, has been recommended and is being implemented to assist in species recovery. To date, Bombus breeding efforts have low mating success. Adapting assisted reproduction techniques from apiculture could increase mating success in captive breeding programmes and support controlled breeding to enhance genetic diversity. To this end, we investigated a new dissection technique for male Bombus species, in which reproductive organs are removed from the abdomen through the cloaca. We found that the pull dissection methodology was more effective at reliable sample collection than dissections performed via the classic methodology (probability of finding sperm in accessory ducts for the classic method = 2.5%, [CI = 0.23%, 14%]; probability of finding sperm in accessory ducts for the pull method = 58%, [CI = 43%, 73%]). By circumventing the need to manipulate the digestive system, this method simplifies the dissection process, increasing the chances of success for novices.

Plant diversification in agroecosystems can support natural enemy diversity by offering varied food resources and shelters. However, these benefits are context-dependent and do not always lead to effective pest control. This study investigates the interactions between Phytoseiidae predatory mites and host plants in vineyard inter-rows. Although inter-row vegetation is known to enhance Phytoseiidae diversity, little is known about which plant species act as key reservoirs and which plant traits promote higher mite abundance and richness. We assessed relationships between the taxonomic and functional diversity of Phytoseiidae (abundance, richness, body and cheliceral size) and six plant traits related to habitat quality and food availability across 11 plant species in a Mediterranean vineyard. Four species: Erigeron sumatrensis Retz, Picris hieracioides L., Crepis foetida L., and Helminthotheca echioides (L.) Holub, hosted particularly high mite densities and richness, indicating their potential as natural enemy reservoirs. The dominant Phytoseiidae species were Typhlodromus (Anthoseius) recki, Typhlodromus exhilaratus and Phytoseius finitimus. Furthermore, plant traits played a key role in shaping mite communities. High trichome density and leaf dry matter content (LDMC) were associated with smaller Phytoseiidae body width. Pollen grain number was positively correlated with Phytoseiidae densities, suggesting that pollen produced by the host plant may serve as an alternative food source. Moreover, leaves with high LDMC values were associated with longer cheliceral digits of Phytoseiidae, potentially enhancing their ability to pierce leaf surfaces to access water or nutrients. Our results highlight the importance of integrating both taxonomic and functional perspectives when studying plant–arthropod interactions. Expanding the range of plant species and traits under study will further clarify how vegetation influences beneficial arthropods. Practically, this knowledge can be used to design inter-row plant mixtures that support predatory mites and promote biological control in vineyards.

The susceptibility of herbivorous mites to acaricides can be influenced by the host plants they inhabit, which may impact the effectiveness of pest management strategies. Red palm mite (Raoiella indica) is a polyphagous mite that infests a variety of plant species, but its interactions with different hosts and susceptibility to acaricides are not fully understood. This study assessed whether differences in suitability of red palm mite to host plants could affect their susceptibility to different acaricides (abamectin, azadirachtin, fenpyroximate, and pyridaben). The following host plants were evaluated: coconut palm (Cocos nucifera), christmas palm (Adonidia merrillii), and foxtail palm (Wodyetia bifurcata). Host suitability was investigated through the instantaneous rate of population growth (ri), while susceptibility to acaricides was investigated using dose–response curves. The susceptibility to acaricides was inversely related to the suitability of the host plant. Thus, coconut palm plants provided the highest ri for red palm mite, and these populations were also the least susceptible to acaricides (abamectin, fenpyroximate, and pyridaben). Azadirachtin failed to reach 100% mortality even at the highest concentrations. Our results suggest that coconut palm is a more suitable host for red palm mite, possibly contributing to the mites' enhanced fitness and tolerance to acaricides. This study highlights the importance of considering host plant effects in pest management strategies and suggests that host adaptation may play a role in acaricide tolerance in red palm mite populations.

This study evaluated the insecticidal potential of an acetonic extract from Jatropha curcas seeds (JcAE) and an enzymatic extract from Serratia marcescens (SmEE). The extracts were applied individually or in combination against Spodoptera frugiperda to assess their effects on larval and pupal mortality, weight, and developmental duration. Bioassays were performed via artificial diet incorporation using control (0 ppm), JcAE (100, 250, 1000 and 2500 ppm), SmEE (40, 80, 150 and 300 ppm), and combined JcAE + SmEE treatments (1000 + 150, 1000 + 300, 2500 + 150 and 2500 + 300 ppm). Larval and pupal mortality, weight reduction, and developmental delays were measured. Mortality data were analysed using Fisher's exact test, while weight and development time were compared via Kruskal–Wallis followed by Dunn's tests, with percentage differences calculated relative to the control. The highest concentrations of JcAE (1000 and 2500 ppm) and SmEE (150 and 300 ppm) caused significant insecticidal activity (77.33%–86.67% cumulative mortality), reduced larval weight (−63.02% to—80.23%) and pupal weight (−8.45% to −22.72%), and delayed development by 4–10 days. Synergistic effects were observed in combined treatments (1000 + 300 and 2500 + 300 ppm), which further increased mortality (90.0%–93.33%), suppressed growth, and extended larval development. Chemical analyses identified seven major fatty acids in JcAE, while SmEE exhibited exo- and endo-chitinase activity. These results demonstrate that JcAE and SmEE, alone or in combination, are viable candidates for the agroecological management of S. frugiperda, as they present a double mechanism of action: toxicity and interruption of development, which may help to achieve sustainable crop production.

Understanding the dispersal ability of insects is critical for conservation efforts, as well as for preventing economic and health risks, such as the spread of bluetongue disease or African swine fever (ASF). However, knowledge of the dispersal ability of a wide range of insect species is limited. One highly unpredictable resource in space and time is carcasses, which provide an ephemeral habitat for the necrophilous insect community. In 2021 and 2022, we marked more than 5000 specimens of the carrion beetle Necrodes littoralis (L. 1758, Coleoptera: Staphylinidae: Silphinae) and released them within a forested landscape with experimentally placed cadavers to test two hypotheses. Our first question was how far N. littoralis could disperse; we hypothesised that the beetles are highly mobile and disperse over more than 3 km, which is the distance currently used for buffer strips around wild boar carcasses infected by ASF. Our second question was if wind affected the colonisation of cadavers by N. littoralis. As beetles locate carrion using olfactory cues, we hypothesised that the probability of cadaver colonisation by insects increases when positioned up-wind. Based on recapture rates of 4%–7% per year, we estimated a mean distance between release and carrion of 6 km using a dispersal kernel. Some individuals were recaptured at distances exceeding 30 km. The probability of colonising an experimental cadaver increased when the resource was placed up-wind, but colonisation probability did not increase consistently over both years with the body mass of the carcasses. Our findings support previous work suggesting high dispersal ability of the carrion beetle N. littoralis, as an adaption to colonising highly ephemeral necromass resources. From a conservation perspective, these results suggest that there are limited dispersal barriers for carrion insects within a management region. From the perspective of disease control, however, these results also indicate that buffer strips of 3 km, as used in ASF mitigation, may not be sufficient to prevent the spread of pathogens by insects.

The characteristics of tropical landscapes play a critical role in shaping the ecological dynamics of pollinators, which are important for both natural ecosystems and agriculture. This study investigates how landscape composition affects colony performance in Apis cerana (Asian honey bee) and Tetragonula laeviceps (stingless bee) across Indonesia. To assess colony performance, interviews were conducted with 59 beekeepers of A. cerana and 82 beekeepers of T. laeviceps from islands across Indonesia; from these, we inferred presence-absence data characterising colony growth, honey production, and bee mortality. Compositions of the landscapes surrounding hives were assessed at different spatial scales using land cover maps derived from the Copernicus satellite dataset and classified using a deep learning algorithm. A binomial generalised linear model (GLM) approach was used to determine the relationship between landscape composition and colony performance. Results showed that environmental factors, especially the numbers of patches and class areas of trees and crops, had different effects on colony growth, honey production, and mortality in A. cerana and T. laeviceps. Colony growth, honey production, and mortality rates of A. cerana were related to the numbers of tree patches and class areas of crops, while T. laeviceps was only affected by the numbers of tree patches for its mortality. This highlights the importance of landscape heterogeneity in promoting bee colony health and productivity in tropical regions, providing valuable insights to inform beekeeping practices and landscape management strategies.