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Bees and some wasp species of the superfamily Apoidea pollinate most of the crops used for food and feed, producing different impacts on agricultural production. Despite the considerable importance of Apoidea, the relevance of this group's impact on global crop production and human diets is controversial.To measure the pollination effect of these insects on crop production, factors such as the myriad of agricultural practices, different crop varieties, fluctuating pollinators' densities, constantly changing environmental conditions, and demands for food items in a diverse diets must be considered. An ‘Apoidea impact factor' (AIF), a value calculated taking into consideration the effect of this superfamily on enhancing crop production through pollination, the diversity of crops in a given area, the area planted by specific crops, and agricultural output, was calculated for 176 agricultural crops. Consistently with previous estimations, our results show that Apoidea have a direct impact on 66% of the 128 most important agricultural crops consumed in the world. However, the analysis of the impact of Apoidea on global production and human consumption revealed a different perspective: Apoidea pollination affects only 16% of the total tonnage output, 14% of the cultivated area, and 9% of the kilocalories consumed. Because 25 of the most cultivated crops in the world do not require, or are slightly affected by Apoidea pollination, and these plants grow in 84% of the world's cropland, constituting 50% of the world's diet, and 89% of the kilocalories consumed by peoples around of the world, the AIF at the world level is reduced to 11% of food consumed, and 6% of the kilocalories. The AIF, when applied to a small geographical scale, for example, the municipality or county level rather than country or state level, becomes more useful identifying areas where bees and wasps have greater impact in agriculture. In this report, we update the widely popular quote ‘One out of every three bites of food we eat is a result of pollinators like honey bees’ to a more accurate one: ‘nearly 5% of the food we eat, and about 10% of the calories we burn have a direct relationship with Apoidea pollination'. This new estimate does not diminish the need for pollinators for many of the world's most nutritious foods, but merely suggests that these foods do not provide an extensive part of the human diet. The AIF can be used to identify specific areas where these pollinators have greater impact and direct conservation efforts directly into them. This approach can serve as a better estimate of the role of these pollinators in our food, using data-driven arguments.
Questing is a host-seeking behavior in which ticks ascend plants, extend their front legs, and wait poised for a chance to attach to a passing host. Hard ticks are ectoparasites of terrestrial vertebrates and because some species vector disease, they are among the most medically important of arthropod pests. All ixodid ticks require blood to survive and reproduce with the number of blood-hosts needed to complete their life cycle varying among species. The vast majority are three-host ticks requiring a different host for each developmental stage: larva, nymph, and adult. A few, including some of the most economically important species, are one-host ticks, that quest only in the larval stage. Questing is a rate-limiting behavior critical to tick survival and disease transmission. For the off-host larval stage, survival is highly dependent on ecological and physiological factors. Yet, off-host larval ecophysiology is often overlooked for the more obvious adult and nymphal tick-host interactions. This review summarizes the literature on ixodid larval questing with emphasis on how specific biotic and abiotic factors affect off-host survival.
Examination of bycatch in traps used for adult mosquito control surveillance and bycatch in larval sampling jars, over the past 21 yr, has revealed a number of new distribution records for arthropods. The literature is reviewed, and new distribution information is presented for 98 species of Diptera, 35 species of Copepoda, 14 species of Lepidoptera, and 1 species each of Hemiptera, Hymenoptera, and Amphipoda. Among the new information generated are new records for the United States, new records for Florida, range extensions, a new phoretic association, and at least eight undescribed species, five of which have been described and named. Examination of bycatch can provide basic identification on species distribution and seasonal abundance that might otherwise go undetected. About one-third of Florida mosquito control programs that responded to a survey indicated that bycatch from surveillance was examined. There was a moderate association between presence of a biologist or entomologist on staff and examination of bycatch. Florida mosquito control programs may be able to help fill knowledge gaps related to the state's arthropod fauna.
Lightning is a common agent of disturbance in many forest ecosystems. Lightning-damaged trees are a potentially important resource for beetles, but most evidence for this association is limited to temperate pine forests. Here, we evaluated the relationship between lightning damage and beetle colonization of tropical trees. We recorded the number of beetle holes on the trunks of trees from 10 strike sites (n = 173 lightning-damaged trees) and 10 matching control sites (n = 137 control trees) in Panama.The trunks of lightning-struck trees had 370% more beetle holes than control trees.The abundance of beetle holes increased with increasing total crown dieback among both control and lightning-damaged trees, and with larger tree diameter among lightning-struck trees. Beetle holes also were more abundant in trunk sections of lightning-damaged trees located directly below a damaged section of the crown.The results of this study suggest that lightning damage facilitates beetle colonization in tropical forest trees and provide a basis for investigations of the effects of lightning-caused disturbance on beetle population dynamics and assemblage structure.
A standardized laboratory procedure tested the limb regeneration abilities of 18 populations (16 species) of lady beetles which were then scored, relative to unoperated controls, based on survival, the proportion regenerating the limb completely or partially, and the magnitude of developmental costs (delayed development, reduced body size) associated with limb ablation. Newly molted fourth instar larvae each had a single foreleg amputated at the base of the femur. All species except Propylea dissecta (Mulsant) showed some complete limb regeneration, with limb regeneration index (LRI) scores ranging from 0.025 to 0.905 out of a possible 1.00 (mean = 0.598). Eriopis connexa Germar, an aphidophagous neotropical species, scored the highest. Widely distributed species that dominate agricultural habitats all scored above 0.75, and the only herbivore, Henosepilachna argus (Geoffroy), scored second from lowest. Prolonged pupal development was the most common cost, occurring in nine species, and correlating negatively with regeneration. Taxonomic distance between species correlated with regeneration, but explained <5% of variation; principal component analysis indicated that the LRI was the main factor distinguishing species. We infer that this capacity is conserved, not because of any adaptive advantage conferred, but because the genes responsible are normally activated during pupal development to generate the adult body plan and reconstitute appendages with direct correspondence to larval progenitors. However, good regeneration capacity was associated with the ecological success of the species. In general, broad geographic distribution, guild dominance, polyphagy, interspecific competitiveness, phenotypic flexibility, and invasiveness were characteristics generally shared by species with high levels of regeneration.
The Monarch butterfly (Danaus plexippus) (Linnaeus 1758) is being considered for up-listing to Endangered under the Canadian federal Species-at-Risk Act due to population declines recorded throughout the annual life cycle. Understanding local population dynamics is therefore necessary to assess the effect of environmental and human induced stressors, and to establish a benchmark from which management success can be measured through time. Using fall count data collected along the Lake Erie shoreline, which captures migrants moving south from the core eastern breeding population in Canada, monarch abundance trends are quantified. Count data from three migration count sites and one roost site were analyzed following similar methods as Crewe and McCracken (2015) to make findings comparable. Two of these datasets are newly compiled and are analyzed here for the first time. Results suggest that during the past 10 yr, the number of migrating monarchs along the north shore of Lake Erie has been stable [mean: –3.05% per year, credibility interval (CI): –13.15, 9.97], which is consistent with changes being observed on the wintering grounds. Only migration counts collected between 1995 and 2018 at the Long Point sites demonstrated significant abundance declines (5.25% per year, CI: –8.60, –1.39), which is a similar results to previous analysis of this dataset. Opportunities for future research are discussed within the context of using monarch count data for future conservation efforts.
In September 2019, destruction of a Vespa mandarinia Smith 1852 nest was reported for the first time in North America in Nanaimo, British Columbia, Canada. In December 2019, the Washington State Department of Agriculture also confirmed the first detection of an adult specimen of V. mandarinia in the United States, in Whatcom County, Washington. Vespa mandarinia is the largest hornet species and is a known predator of several insects, including the European honey bee (Apis mellifera) (Hymenoptera: Apidae) (Linnaeus, 1758). The establishment of V. mandarinia in North America poses a serious threat to apiculture, and this species is considered an actionable quarantine pest. Here we report details of the first detection of this species in the United States and use genetic sequence data obtained from five specimens across the globe to estimate differences in origin of the Canadian and U.S. detections. The full mitochondrial genomes of four V. mandarinia specimens representing different geographic locations were sequenced and compared with an existing reference genome. A maximum likelihood tree using 13 protein-coding regions from mitochondrial DNA suggests that the Canada and U.S. specimens are from two separate maternal lineages. A large-scale survey is currently underway to assess the level of Asian giant hornet establishment in both countries and to determine the future direction of eradication efforts.
Promecognathus (Carabidae) includes beetles that are specialist predators whose prey are polydesmidan millipedes that produce highly toxic hydrogen cyanide and benzaldehyde as a defense, and it is unknown how Promecognathus overcomes these chemicals. We observed Promecognathus laevissimus (Dejean, 1829) and P. crassus (LeConte, 1868) in the laboratory and found that they did not use behaviors to avoid the chemical defenses of their prey, Xystocheir dissecta (Wood, 1867) (Polydesmida: Xystodesmidae). We tested benzaldehyde as a feeding deterrent and found noticeable deterrence in all carabid beetles tested except Promecognathus species and Metrius contractus (Eschscholtz, 1829). A total of 18 carabid species were exposed to cyanide vapors in an enclosed chamber for 10 min to determine their relative tolerances. Promecognathus and M. contractus were unaffected by HCN exposures 7–15 times greater than quantities that knocked down all other species. Promecognathus laevissimus and M. contractus were then exposed to high levels of HCN for 2 h, and while individuals of M. contractus succumbed, all P. laevissimus were still moving after 2 h. It is possible that Promecognathus evolved a high tolerance to cyanide as part of a suite of adaptations related to millipede predation. However, we have no plausible explanation for the high tolerance in Metrius, for which there is no evidence of millipede feeding. This is the first documented case of predatory insects that exhibit high tolerance and potential resistance to cyanide. Possibly, these beetles have a detoxification mechanism that is not cyanide specific, as their tolerance level far exceeds any dose they would encounter in their natural habitat.
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