Abstract Pathogen spillover from managed to wild pollinators represents an emerging threat to global pollinator diversity. However, surveillance of microbial pathogens in tropical wild bee communities remains severely limited. We investigated Nosema ceranae detection prevalence in the orchid bee Euglossa imperialis across seasons at 2 ecologically contrasting sites in the Panama Canal corridor: a protected tropical forest and a semi-urban landscape. Using species-specific polymerase chain reaction (PCR) assays, we detected N. ceranae DNA in gut tissues of this euglossine bee. Detection prevalence was significantly higher at the protected forest site (34/44; 77.3%) than at the semi-urban site (12/38; 31.6%), with no seasonal effect observed. A literature synthesis revealed that Nosema parasites have been reported across at least 9 hymenopteran families, with N. ceranae showing the broadest distribution of reported associations among named species, including detections in managed and wild bees as well as social wasps. This study provides the first molecular detection of N. ceranae in E. imperialis and indicates that N. ceranae DNA is detectable in wild pollinator communities at 2 ecologically contrasting sites in the Panama Canal corridor. The higher detection prevalence at the forest site suggests that local spatial or ecological context may be an important correlate of exposure in this system, a hypothesis that will require testing with additional replicated sites and environmental covariates. These findings highlight the need for expanded pathogen monitoring in Neotropical pollinator communities and underscore the importance of integrating ecological surveillance with molecular diagnostics to assess emerging pathogen risks in tropical ecosystems.
Abstract Intensive agricultural production can reduce beneficial insects by limiting access to undisturbed habitat. Wildflower plantings are promoted as conservation strategies to support pollinators and natural enemies on farms, yet their effects on certain crop pests remain understudied. We evaluated whether wildflower plantings adjacent to highbush blueberry (Vaccinium corymbosum L.) fields increased natural enemy abundances and reduced Drosophila suzukii populations compared to fields without this practice. In 2019 and 2020, across 12 farms in Michigan representing 3 management types (conventional management without wildflower plantings, conventional with wildflower plantings, or no chemical pest management), we quantified natural enemies, monitored adult D. suzukii abundance and fruit infestation, and measured removal of D. suzukii pupae. Unsprayed fields supported the highest natural enemy abundance and pupal removal but also had the highest D. suzukii abundance. There was some limited evidence for wildflower plantings increasing natural enemies, such as post-harvest, but overall, there was no significant difference between conventionally managed sites with and without wildflower plantings, and no impact on D. suzukii pupal removal. Additionally, wildflower plantings increased D. suzukii adult abundances post-harvest and in the wildflower plantings compared to mown field margins. Fruit infestation generally remained low in conventionally managed fields irrespective of wildflower plantings. Together, these results suggest that wildflower plantings only provide limited benefits for natural enemies and do not aid in D. suzukii control. Though typically established for pollinators, understanding how habitat enhancements impact particular pests of concern is essential for designing strategies tailored to specific production systems.
The elm borer, Saperda tridentata (Olivier, 1795) (Coleoptera: Cerambycidae), is a North American longhorn beetle that has been repeatedly intercepted in Europe on imported elm logs. Although climatic conditions are considered suitable for its establishment, uncertainty remains regarding the suitability of European tree species as hosts. We evaluated the potential host range of S. tridentata by testing 4 elm species (Ulmus glabra, Ulmus laevis, Ulmus minor, and Ulmus pumila), 3 maple species (Acer campestre, Acer platanoides, and Acer pseudoplatanus), and 3 poplar species (Populus alba, Populus nigra, and Populus tremula) that are widespread in Europe. No-choice and choice feeding bioassays were conducted to assess adult feeding preference, while no-choice development bioassays were performed to determine whether larvae could establish and develop within logs of the tested species. Adults fed on all elm species but showed no feeding activity on maples or poplars. Feeding levels on European elms did not differ significantly from those recorded on the primary North American host, U. americana. Larvae were recovered from logs of all 4 European elm species, confirming their suitability for larval establishment, whereas no larvae were found in maple or poplar logs. Adult emergence was limited, with only 3 individuals emerging from U. minor logs. Our results indicate that European elm species can support both adult feeding and larval development of S. tridentata, whereas the tested maple and poplar species appear to be unsuitable hosts. These findings suggest that host availability is unlikely to limit the establishment of S. tridentata in Europe if introductions occur.
The foxglove aphid, Aulacorthum solani (Kaltenbach), is a major economic pest in Asian soybean fields. Previous studies on its life parameters often used detached soybean leaves, which may not accurately reflect development and reproduction due to disrupted nutrient flow. This study compared survival, development, and reproduction of A. solani on living versus detached leaves at 19, 22, 25, 28, 31, and 34 °C. Between 19 and 28 °C, aphids developed and reproduced successfully on both leaf types. At 31 °C, nymphs failed to mature on detached leaves but reached adulthood on living leaves, though no nymphs were produced. At 19, 22, and 25 °C, fecundity and net reproductive rate were overestimated on detached leaves. At 28 and 31 °C, adult longevity, total longevity, oviposition day, fecundity, intrinsic and finite rates of increase, and net reproductive rate were underestimated on detached leaves. The mean developmental rate (y, reciprocal of nymph duration) on living leaves in relation to temperature (x) follows the equation y = 0.0088 x-0.0717. The lower developmental threshold is 8.15 °C, and the effective cumulative temperature required for nymph-to-adult development is 113.64 degree-days. On detached leaves, the equation y = 0.0055 x + 0.0043 yields an invalid threshold of -0.78 °C and 181.82 degree-days. These findings underscore the necessity of using living soybean leaves for accurate life table studies of A. solani, critical for predicting field populations and improving control strategies.
Insects represent a major component of terrestrial biodiversity and ecosystem function, yet the environmental drivers of occurrence and detection remain poorly understood for many ground-dwelling taxa. Environmental gradients can influence both whether insect taxa occupy habitats and how frequently they are detected during sampling. Rhaphidophoridae (cave crickets) are moisture-dependent, ground-dwelling orthopterans associated with caves, rock crevices, and forest-floor refuges. Here, we used occupancy models that account for imperfect detection to examine how habitat structure and elevation influence detection and occupancy probabilities of Rhaphidophoridae across 75 sites, each measuring 1 hectare, in Hidalgo, Mexico. Rhaphidophoridae were present in 33 of 75 sites. The best supported model indicated that detection probability increased with forest-associated habitat structure (tree and shrub cover, deep leaf litter, refuge availability, and low disturbance), whereas occupancy probability increased with elevation. Herbaceous cover did not predict occupancy but was negatively associated with detection. These findings suggest that broad environmental gradients constrain occurrence, whereas detectability is associated with forest structure and lower human disturbance. Our study provides new ecological data on Rhaphidophoridae in Mexico and demonstrates how distinguishing between drivers of occupancy and detection can improve ecological inference from field surveys.
