Insects最新文献

Temperature and host fruit availability are key factors influencing the life history traits of the Mediterranean fruit fly (medfly) (Ceratitis capitata). This study examines how developmental temperature and host fruit type affect adult longevity and fecundity in medflies from six populations spanning Southern to Central Europe. Larvae were reared on apples and bitter oranges at three constant temperatures (15, 20, and 25 °C), with pupae maintained under the same thermal conditions until adult emergence. Adults were then kept at 25 °C, with longevity and fecundity recorded daily. The results showed that higher developmental temperatures increased adult lifespan across all populations, regardless of host fruit. Similarly, fecundity rates in ovipositing females were higher at higher temperatures. Reproductive periods (pre-oviposition, oviposition, and post-oviposition) varied among populations, indicating population-specific responses. These findings underscore how temperature and host fruit availability shape medfly invasion dynamics, highlighting the species' biological plasticity and adaptation to different environments. This research provides valuable insights for pest management, particularly in the context of climate change, offering strategies to mitigate the spread of medflies into new regions.

The honeydew moth, Cryptoblabes gnidiella Millière (Lepidoptera: Pyralidae), is native to the Mediterranean Basin. However, it has recently been reported as an emerging grapevine pest in southern European Union countries and in the Middle East, North Africa, and South America. This may be attributed to the global warming trends. In this brief communication, we present the first documented cases of honeydew moth infestation of grapevine in Greece, specifically in two organic vineyards in the Regional Unit of Drama in Northeastern Greece in 2024. Notably, the infestations were limited to the late-ripening grape cultivar 'Xinomavro', harvested in October, while other cultivars such as 'Assyrtiko', 'Malagousia', 'Cabernet sauvignon', 'Sauvignon blanc', 'Limniona', 'Chardonnay', and 'Agiorgitiko', harvested in late August and early September, showed no signs of infestation. This suggests that the actual impact of C. gnidiella in Greece may be underestimated, as previous late summer infestations of lepidopteran larvae in vineyards were likely misattributed to L. botrana. We discuss the potential implications and concerns regarding the occurrence and management of this pest in Greece.

This study explored the thermal response of Drosophila suzukii, an injurious insect pest present in many countries worldwide, at different controlled conditions. This species is responsible for several economic losses in soft fruit cultivations, develops on ripening fruits, and has the capability to quickly adapt to new territories and climates, closing multiple generations per year. Given its high invasive potential and the increasing need for low-impact control strategies, an in-depth exploration of the biology of this species and of the stage thermal response is fundamental. Specimens of an Italian strain from Apulia were reared in growth chambers at different constant temperatures (6, 9, 13, 18, 20, 24, 25, 26, 27, 28, 29, 31, 32 and 33 °C). The life cycle of each specimen was individually tracked from the egg to the death of the adults, considering the larval stages distinction as well. Besides development and mortality, egg production over temperature has been recorded. The dataset was first analysed according to life tables studies; then, we also estimated the biological parameters of the most common equations describing development, mortality, and fertility involved in physiologically-based model applications. The results confirmed and extended the information on the thermal response already present in the literature, but with reference to a population adapted to warmer climates. The species successfully developed from egg to adult at 13-29 °C, while between 6-9 and 29-33 °C the development was limited to L2/L3 stages. Optimal temperatures are around 26-28 °C, depending on the life stage. This study provides one of the complete overviews of the thermal response of D. suzukii, which is available in the current literature, and opens the door to more accurate modelling frameworks.

Thermal polymorphism, usually represented by thermal melanism (darker coloration in cooler habitats), is a well-known phenomenon in animals. In Cetoniinae, several species in captivity tend to become darker after several generations of breeding, which is probably caused by a lower temperature than is typical for their native habitats. Pachnoda iskuulka is a beetle species occurring in Somaliland. This species is easy to breed in captivity, and it is colorful and variable in the proportions of yellow, red, and black coloration. We kept this species from the first instar larva to the adult stage at three different temperatures. Elytra and pronotum of the adults were photographed, and proportions of the three main colors were measured. The proportion of black coloration significantly increased with size and decreased with temperature, while the proportion of yellow color increased. This species is certainly thermally polymorphic, which can be an adaptation for activation even at lower temperatures. The possible mimicry with beetles of the genus Hycleus is discussed. It is the first confirmation of thermal polymorphism in Cetoniinae and one of a few in Coleoptera.

Many social and environmental variables can affect the interactions among individuals in an insect colony that fundamentally structure its social organization. Along with important attributes such as age and caste, immunity-related factors such as the performance of sanitary tasks or exposure to a pathogen can also influence an individual's social interactions and their place in the resulting social network. Most work on this subject has supported the hypothesis that health-compromised individuals will exhibit altered social or spatial behavior that presumably limits the spread of infection. Here, we test this hypothesis using honey bee workers recently involved in hygienic behavior, an important set of sanitary tasks in which unhealthy brood are uncapped and then removed from the colony. Using static social networks, we quantify the interaction patterns of workers recently involved in hygienic tasks and compare their network centrality to non-hygienic workers. Using dynamic networks, we analyze the capability of hygienic workers to spread a potential infection throughout the colony. We find no substantial differences in how connected hygienic workers are in the network, and we show that hygienic workers would spread a novel infection throughout the colony to the same extent as non-hygienic workers. Our results suggest that experience with certain sanitary tasks may not necessarily produce rapid changes in social behavior. This work highlights the importance of considering the benefits of remaining socially integrated in important information networks and the temporal limitations for how quickly organized immune responses can occur in response to potential infections.

The ladybirds Coccinella septempunctata and Harmonia axyridis are important biocontrol agents for the small walnut aphid Chromaphis juglandicola, a key walnut pest. C. juglandicola outbreaks occur in walnut orchards, and walnut yields have declined. Intraguild predation (IGP) is prevalent among natural enemies that coexist in shared habitats and prey upon the same extraguild prey. We designed laboratory experiments to evaluate the potential for IGP between these two ladybirds at different temperatures and extraguild (EG) prey densities, and the ability of IGP to control EG prey under different conditions. We measured IGP rates in first instar larvae, female adults, and male adults (both starved for 24 h) in the vulnerable immature life stages of two ladybird eggs. Intraguild (IG) prey (H. axyridis eggs or C. septempunctata eggs) and EG prey (C. juglandicola) consumption were tallied after 24 h. Temperature and EG prey density influenced IGP rates, with temperature contributing the most to the variance. IGP increased with increasing temperature (15-35 °C), with both factors interactively influencing the EG prey consumption rate and exhibiting highly significant effects. EG prey consumption increased with temperature and density. This research provides theoretical support for the rational use of H. axyridis and C. septempunctata in the joint biological control of C. juglandicola.

Prior to implementing watershed-wide projects to reduce the impacts of agriculture on regional streams and rivers, stream habitats and benthic aquatic macroinvertebrate communities were assessed at 15 sites on the South Branch Root River and its major tributaries in southeastern Minnesota, USA. Triplicate kick-net samples were collected from each site during three time periods (1998, 1999, 2006/2008) and stream habitats were inventoried within 150 m long sections at each site. In total, 26,760 invertebrates representing 84 taxa were collected and used to rate stream sites using a regional multi-metric benthic index of biotic integrity (BIBI). BIBI scores were significantly correlated with total invertebrate taxa richness. BIBI ratings improved from poor and very poor at headwater sites in channelized stream sections draining agricultural lands to fair to good to excellent in downstream sections flowing through natural channels in largely forested lands. Fifty percent of samples rated stream sites as poor or very poor. Over 85% of stream habitat assessments indicated the presence of fair to good habitats, although stream sites were relatively wide and shallow and dominated by fine sediments that also embedded coarser substrates. BIBI metrics and scores were strongly positively correlated with pool area, riffle spacing-to-stream width ratios, and silt-free substrate, and negatively correlated with width-to-depth ratios. Most stream sites had few Ephemeroptera, Plecoptera, Trichoptera, and Diptera taxa and too few intolerant taxa. It is expected that benthic invertebrate communities should improve as more riparian buffers are added along all streams. However, on-going channel maintenance activities in headwater stream sections, mandated to encourage drainage of adjacent agricultural fields, will continue to negatively impact headwater habitats and biotic communities.

To date, no study has been conducted to investigate the diversity in honeybee populations of Apis mellifera in the Czech Republic. Between 2022 and 2023, worker bees were collected from colonies distributed throughout the Czech Republic in 77 districts, and their genetic differences were examined using 22 microsatellite loci. The samples were obtained from hives (n = 3647) and through the process of capture on flowers (n = 553). Genetic diversity parameters were assessed for both populations in all 77 districts. The findings demonstrated that honeybee populations exhibit moderate genetic diversity, as evidenced by the number of observed alleles, the Shannon index, and heterozygosity values. There was no discrepancy in diversity between hive and flower samples. Diversity characteristics were determined: mean observed heterozygosity 0.55 (hives) and 0.56 (flowers), and fixation index 0.58 for both populations. The average number of alleles per locus was 13.77 and 11.18 from hives and flowers, respectively. The low F_ST and F_IS values (they measured the level of genetic differentiation between populations and the level of inbreeding, respectively) suggest the absence or minimal genetic diversity within and among studied populations. The genetic variation was calculated as 2% and 1% between populations, 8% and 6% between individuals within populations, and 91% and 93% between all individuals in samples from hives and flowers, respectively. Cluster and DAPC (discriminant analysis principal component) analysis classified the bee samples collected from across the country into three and five to six distinguishable groups, respectively. The honeybee population in the Czech Republic displays sufficient diversity and a partial structure. However, there appears to be no correlation between the genetic groups and the geographic regions to which they are assigned.

The ambrosia beetle Euwallacea interjectus Blandford (Coleoptera: Curculionidae: Scolytinae) has recently emerged as a pest in Chinese poplar plantations, causing significant economic losses through damage to host trees in association with its mutualistic fungus Fusarium populicola. This study evaluated the biocontrol potential of Beauveria bassiana strain B-BB-1, Serratia marcescens strain B-SM-1, its metabolite prodigiosin, and two ectoparasitic mites, Pyemotes moseri and Pyemotes zhonghuajia. B. bassiana exhibited significant lethality toward adult female E. interjectus, reduced offspring production, and inhibited F. populicola growth. S. marcescens and prodigiosin had certain lethal effects on larvae and inhibited the growth of F. populicola. Both mites effectively parasitized beetle pupae and larvae, with no significant differences in efficacy between the two species. These agents demonstrate promise for the biological control of E. interjectus, offering insights for managing ambrosia beetle infestations.

Subcortical beetle communities interact with a wide range of semiochemicals released from different sources, including trees, fungi, and bark beetle pheromones. While the attraction of bark beetles, their insect predators, and competitors to bark beetle pheromones is commonly studied, the attraction of these beetle communities to other sources of semiochemicals remains poorly understood. We tested the attraction of bark and wood-boring beetles and their predators to host stress volatiles, fungal volatiles, and a mountain pine beetle lure in the field. Host stress volatiles were derived from lodgepole pine trees stressed by three fungal symbionts of mountain pine beetle and two common phytopathogens. Our results showed that bark beetles, particularly mountain pine beetles, show a preference for a combination of fungal volatiles, particularly 2-methyl-1-butanol and its lures. Without the addition of lures, 2-methyl-1-butanol was also identified as a key fungal volatile in the attraction of mountain pine beetle competitors from the Cerambycidae and Buprestidae families. Predators in the Elateridae and Staphylinidae families showed attraction to host stress volatiles and the healthy tree volatile profiles. These findings suggest that these semiochemicals warrant further field testing for potential use in monitoring and management of subcortical beetle populations.