Environmental Entomology最新文献

Wild bee communities are the target of various conservation and ecological restoration programs. Strategic conservation can influence bee communities visiting fields and help mitigate pollinator limitations in fruit production. However, planning compatible conservation strategies and gauging their effectiveness requires understanding how local communities vary across space and time in crops and adjacent semi-natural areas. Here, we assessed the spatiotemporal changes in the composition of wild bee communities in blueberry fields and adjacent forests. In partnership with commercial farms in southeast Georgia, USA, we deployed blue vane traps at the interior and edge of blueberry fields and within adjacent forests of 8 fields, from March to October over 2 yr. We identified 72 wild bee species across 26 genera. The most common were Melissodes communis (Cresson, Hymenoptera: Apidae), Bombus bimaculatus (Cresson, Apidae), Melissodes bimaculatus (Lepeletier), Ceratina floridana (Mitchell, Apidae), Lasioglossum pectorale (Smith, Halictidae), and Lasioglossum nymphale (Smith), which accounted for nearly 60% of the wild bees caught. Bee diversity and richness fluctuated over time, with peaks in all 3 habitat types occurring after the blueberry blooming. Bee abundance in the adjacent forest was relatively constant throughout the season, while in the field interior and edge assemblages, abundance peaked between May and June. We observed dissimilarity in species composition related to month and field location. This difference was explained by fluctuation in the identity and relative abundance of the most abundant species. Together, our study advances foundational knowledge of wild bee community dynamics and species identity in blueberry fields which will help inform and prioritize conservation practices.

Joshua Tree National Park (JOTR) in southern California offers a unique opportunity to explore insect biodiversity across 2 distinct desert ecosystems: the lower-elevation Sonoran Desert and the higher-elevation Mojave Desert. In these harsh environments, many blow flies (Diptera: Calliphoridae) serve as important decomposers, feeding on animal waste and decomposing tissue. Some blow fly species, notably non-native species, are associated with human activity, which underscores the need to study their communities in JOTR, where annual visitation has reached 3 million. This study investigated the community composition of blow flies across the park and assessed the impact of visitor activity on blow fly communities in JOTR. Sampling from 2021 to 2023 using traps baited with squid carcasses revealed higher blow fly diversity in the Mojave Desert relative to the Sonoran Desert, in contrast to previous insect and vegetation surveys within the park. Across the park, blow fly community composition (i.e., β-diversity) differed by season. Blow fly abundance, richness, and diversity were similar between low- and high-visitor activity sites. However, more non-native species were collected in areas of low visitor activity, suggesting regular waste removal practices in high-visitation sites might limit their ability to complete development as secondary colonizers. This study is the first to characterize blow fly communities in Joshua Tree National Park. These findings demonstrate that blow fly communities reflect previously established park boundaries and underscore the importance of waste management practices in reducing the spread of non-native species throughout the park.

Microplastics (MPs) are a growing problem worldwide. Soils are long-term storage sinks of MPs because of the many pathways they enter the soil and their long degradation period. Knowing how MPs influence soil organisms, the effects of organisms on the fate of MPs, and what this means for soil additions, losses, transformations, and translocations is paramount. MPs in soil could impede the breakdown of organic matter by adult darkling beetles. We set up an experiment to test this hypothesis by adding finely ground scrap tire rubber to organic soil and a small population of adult darkling beetles (Zophobas morio, Fabricius 1776, Coleoptera: Tenebrionidae). The beetles are omnivores that accelerate the breakdown of soil organic matter when feeding on soil detritus. As a control, we released beetles into organic soil with no MPs. We also surveyed published manuscripts on the effects of MPs on insects, decomposers, and decomposition in soil, providing a reference frame for our findings. Darkling beetles ate, fragmented, and humidified the soil mixture, enhancing microbial decomposition. All treatments lost weight over the experiment period, with the control losing 10%, significantly more than the other treatments (an average loss of 5%). Higher concentrations of microplastics in soils led to lower reductions in soil mass through decomposition. These findings suggest that MPs impede detritivores from breaking down soil organic matter. Even so, only a handful of studies evaluated the effects of tire particles on soils and detritivores in the literature survey. Still, these particles are among the largest sources of MPs on land.

The growing expansion of eucalyptus plantations in Brazil and the impact of exotic pests, such as Gonipterus platensis, demand effective, and sustainable biological control strategies. The aim of this study was to assess the pathogenicity of 10 Bacillus thuringiensis (Bt) isolates to neonate Gonipterus platensis larvae, commonly known as the eucalyptus weevil (Coleoptera: Curculionidae) with the specific focus of evaluating their potential to manage this pest while preserving its egg parasitoid, Anaphes nitens. To achieve this, the genomic DNA of the 10 Bt isolates was extracted using the thermal lysis method for molecular characterization of their Cry and Vip proteins. Neonate G. platensis larvae were subjected to bioassays with each isolate, at a concentration of 1 × 109 spores/ml, was applied on 10 larvae per replication (3 replications). The concentration and lethal time to kill 50% of the larvae were determined for the most effective isolates. The Bt isolates 107 and 178 isolates even at concentrations 10× lower than those recommended for commercial Bacillus thuringiensis var. tenebrionis (Btt) formulations against Coleoptera pests, achieved 100% mortality of G. platensis larvae. These isolates, with coleopteran-specific genes, caused high mortality of neonate Gonipterus platensis larvae. This indicates their potential for the biological control of this pest and maybe of other Coleoptera pests. Their use poses minimal risk to non-target organisms such as the egg parasitoid A. nitens and indicates a promising avenue for integrated pest management strategies with effective pest control while preserving the ecological balance.

Histia rhodope (Cramer) (Lepidoptera: Zygaenidae) is one of the most destructive defoliating pests of the landscape tree Bischofia polycarpa (Levl.) S in China and other Southeast Asian regions, posing a critical threat to urban landscapes and their ecological benefits. This pest has shown a trend of northward range shift in recent years in China, making it urgent to understand its potential distribution. This study investigated the cold tolerance of overwintering H. rhodope larvae from October 2022 to March 2023 and estimated their overwintering potential in China. The results showed that the supercooling points (SCP) differed significantly across months. The SCP tended to decrease as the ambient temperature dropped until January, after which it gradually increased until the end of winter. The highest monthly mean SCP was -7.5 ± 2.22°C (October 2022), while the lowest monthly mean SCP was -15.09 ± 2.61°C (January 2023). The mortality rate increased with longer exposure times and lower exposure temperatures but decreased as winter progressed. Moreover, 50% and 90% lethal temperature (Ltemp50 and Ltemp90) exhibited a similar trend, decreasing to a minimum in January 2023, which indicates increased cold tolerance during the colder months. Using Ltemp90 in January as the isotherm for its northern limit indicated that H. rhodope may be limited by low temperatures along the 40°N latitude. These results provide a basis for predicting the dispersal potential and possible geographic range of this pest in China.

Understanding the movement and distribution patterns of insects is crucial for developing effective stored grain management protocols. This research investigates 3-dimensional movement and distribution of Tribolium castaneum (Herbst) and Cryptolestes ferrugineus (Stephens) separately at different temperatures (5, 10, 20, and 30°C) and for different movement periods (1, 2, 3, and 24 h) in stored wheat with a uniform moisture content of 14.5% (wet basis). The experiments were conducted in a wooden container with internal dimensions of 0.7 × 0.7 × 0.7 m. The wheat was filled into 343 mesh cubes (referred to as cubes), each measuring 0.1 × 0.1 × 0.1 m, arranged in 7 layers after being loaded into the container. One hundred insects were introduced into the center cube (the center of the container) at the start of each experiment. After the desired movement period, the cubes were removed in less than 45 min from the wooden container. The wheat in each cube was wrapped in labeled plastic bags, sieved, and the insects were recovered and counted. Results indicated that both species exhibited movement speeds > 7.2 m/d in vertical and horizontal directions at higher temperatures (20 and 30°C). At lower temperatures (5 and 10°C), their vertical speed was higher than their horizontal speed. Tribolium castaneum ceased movement at 5°C, whereas ~13% of C. ferrugineus adults continued to move at this temperature. The drift effect and geotaxis influenced the movement and distribution of both species in the vertical direction, while their horizontal movement followed a diffusion pattern.

Planting native flora is a popular conservation strategy for pollinators. When searching for native plants, consumers may encounter cultivars of native plants, which can have different phenotypic traits than plants found in wild populations ("wild-type native plants"). Previous research evaluating pollinator visitation to wild-type native plants and native cultivars has yielded mixed results, in terms of whether their visitation rates are similar or distinct. We established a garden experiment in Corvallis, Oregon, to examine pollinator visitation and utilization of Pacific Northwest native plant species and cultivars. Over 3 years, we collected and observed bees (Hymenoptera: Apoidea), butterflies (Lepidoptera: Papilionoidea), and syrphid flies (Diptera: Syrphidae) to understand (i) if plant pairs had different visitation rates, (ii) whether any pollinators were associated with differential visitation, and (iii) if specialist taxa preferred wild types over cultivars. Pollinator visitation rates varied by plant and pollinator groupings, but in comparisons between native plant and cultivar pairs, native plants were preferred 37.2% of the time (n = 29 comparisons), cultivars 7.7% of the time (n = 6), and there was no difference in 55.1% of comparisons (n = 43). Our pollinator community data found native plants had greater observed total pollinator richness (except for 1 tie) and bee richness than cultivars, though predicted richness varied. Specialist bees were collected more often from wild types. Cultivars with high visitation rates were minimally developed selections, as opposed to interspecific hybrids. Our results join a growing body of literature in suggesting wild-type native and minimally developed plants should be emphasized for supporting pollinator fauna.

Facultative diapause is a life history trait that allows insects to undergo continuous development when conditions are favorable or to enter diapause when they are not. Insect voltinism can have an impact on the success of a weed-biological control agent because additional generations can increase agent population growth and reduce late-season recovery in the target weed. The most common factors that cue diapause are photoperiod and temperature; however, the role of nutrition is increasingly being recognized. We conducted a laboratory experiment to examine the effects of photoperiod and foliage age on diapause induction, pupal weight, and pupal development time in Hypena opulenta (Christoph) (Lepidoptera: Erebidae), a biological control agent for invasive swallow-worts in North America. A factorial experimental design was employed whereby H. opulenta was reared at long (16:8 h light:dark) and short (12:12 h) photoperiods on young and old swallow-wort foliage (Vincetoxicum rossicum Kleopow) Barbar. (Apocynaceae). Photoperiod was the only factor that affected diapause induction in H. opulenta. While foliage age did not affect diapause induction, it did affect pupal weight and pupal development time, with older foliage resulting in lower pupal weight and extended pupal phase. In field conditions, these impacts could affect pupal mortality through reduced winter preparedness and increased exposure to predators. These results support H. opulenta voltinism models based on photoperiods and indicate that the tendency of captive-reared H. opulenta to enter diapause after 2 or 3 generations, even in the absence of short photoperiods, is not a result of changing foliage age.

Some coniferophagous bark and woodboring beetles overlap spatially and temporally in host trees. These larval interactions have been classified as competitive and predatory in favor of the larger and more mobile woodborer larvae. In some bark beetles, larval traits have been reported that facilitate evasion of woodborer larvae. Both bark beetles and woodborers mediate mating on host material with volatile pheromones. Although it is known that some woodborers eavesdrop on bark beetle aggregation pheromones to facilitate host location, it is not known what effect woodborer pheromones have on bark beetles. The pheromone monochamol is used by most Monochamus spp. Dejean and coniferophagous species from this genus co-occur with bark beetles in host tissues. Because of the negative consequences these larval interactions have for bark beetles, we hypothesized that the woodborer pheromone monochamol would inhibit captures of sympatric and synchronic bark beetles to intercept traps baited with their aggregation pheromones and host volatiles. We tested this hypothesis in 2 systems, 1 in Ontario, Canada, and another in Setúbal, Portugal with field trapping experiments. Trap captures of Ips sexdentatus (Boerner) (Coleoptera: Scolytinae), Orthotomicus erosus (Wollaston) (Coleoptera: Scolytinae) (2 bark beetle species captured in Portugal), and Ips pini (Say) (Coleoptera: Scolytinae) (1 bark beetle species captured in Canada) were reduced by the presence of monochamol. These results suggest that an additional evasion mechanism in some bark beetles is the detection of the woodborer pheromone monochamol and subsequent reduced response to aggregation pheromone and host volatiles in the presence of this woodborer pheromone.