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1. Biogeographical evaluation and conservation assessment of arboreal leafhoppers in the Mexican Transition Zone biodiversity hotspot

   https://doi.org/10.1111/ddi.13254  

   Pinedo‐Escatel, Jorge Adilson ; Aragón‐Parada, Juvenal ; Dietrich, Christopher H. ; Moya‐Raygoza, Gustavo ; Zahniser, James N. ; Portillo, Liberato ; Hou, ed., Zhonge ( March 2021 , Diversity and Distributions)

   Mexico harbours a diverse fauna comprising more than 1,400 leafhopper species, 60% of which appear to be strictly endemic, with many apparently restricted to particular habitats and host plants. The aims of this study were to identify areas of high species richness and endemism, and determine the biogeographic affinities of species in the diverse arboreal tribe Athysanini to provide data useful for conservation prioritization.

   Mexico.

   A data set of 643 historical occurrence records based on authoritatively identified specimens from museums, recent fieldwork, literature and digital repositories was analysed. Analyses of species richness and areas of endemism were conducted using geographic information systems.

   A total of 164 species belonging of 50 genera were included, of which 145 species of 31 genera are considered to be endemic. The Mexican state of Guerrero yielded the most species records (48%). The highest numbers of taxa and endemic species were concentrated along the Mexican Transition Zone (MTZ) within which the Trans‐Mexican Volcanic Belt (TVB) province had the most species records. Endemicity analyses showed two different geographical patterns but similar species richness weights with overlapping values over the MTZ. Distribution across vegetation types was not uniform, with most athysanine species concentrated in the dry tropical forest (65%). Species were documented at elevations between sea level and 3,200 m a.s.l. with three altitudinal preference classes. Conservation assessments applying IUCN criteria categorized a majority of species (145) as endangered or critically endangered.

   Our findings suggest that most identified areas of high species richness throughout the territory have predominantly endemic taxa. Distributional patterns found are non‐random, influenced by richness and endemism values over the TVB province and in the MTZ with a variable dispersion among species. Data highlight a greatly threatened status by habitat loss, remarking an urgent need for an improved conservation framework.

    

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2. Global flows of insect transport and establishment: The role of biogeography, trade and regulations

   https://doi.org/10.1111/ddi.13772  

   Fenn‐Moltu, Gyda ; Ollier, Sébastien ; Bates, Olivia K. ; Liebhold, Andrew M. ; Nahrung, Helen F. ; Pureswaran, Deepa S. ; Yamanaka, Takehiko ; Bertelsmeier, Cleo ( September 2023 , Diversity and Distributions)

   Non‐native species are part of almost every biological community worldwide, yet numbers of species establishments have an uneven global distribution. Asymmetrical exchanges of species between regions are likely influenced by a range of mechanisms, including propagule pressure, native species pools, environmental conditions and biosecurity. While the importance of different mechanisms is likely to vary among invasion stages, those occurring prior to establishment (transport and introduction) are difficult to account for. We used records of unintentional insect introductions to test (1) whether insects from some biogeographic regions are more likely to be successful invaders, (2) whether the intensity of trade flows between regions determines how many species are intercepted and how many successfully establish, and (3) whether the variables driving successful transport and successful establishment differ.

   Canada, mainland USA, Hawaii, Japan, Australia, New Zealand, Great Britain, South Korea, South Africa.

   To disentangle processes occurring during the transport and establishment stages, we analysed border interceptions of 8199 insect species as a proxy for transported species flows, and lists of 2076 established non‐native insect species in eight areas. We investigated the influence of biogeographic variables, socio‐economic variables and biosecurity regulations on the size of species flows between regions.

   During transport, the largest species flows generally originated from the Nearctic, Panamanian and Neotropical regions. Insects native to 8 of 12 biogeographic regions were able to establish, with the largest flows of established species on average coming from the Western Palearctic, Neotropical and Australasian/Oceanian regions. Both the biogeographic region of origin and trade intensity significantly influenced the size of species flows between regions during transport and establishment. The transported species richness increased with Gross National Income in the source country, and decreased with geographic distance. More species were able to establish when introduced within their native biogeographic region.

   Our results suggest that accounting for processes occurring prior to establishment is crucial for understanding invasion asymmetry in insects, and for quantifying regional biosecurity risks.

    

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3. Diversity of Nearctic Dragonflies and Damselflies (Odonata)

   https://doi.org/10.3390/d14070575  

   Abbott, John C. ; Bota-Sierra, Cornelio A. ; Guralnick, Robert ; Kalkman, Vincent ; González-Soriano, Enrique ; Novelo-Gutiérrez, Rodolfo ; Bybee, Seth ; Ware, Jessica ; Belitz, Michael W. ( July 2022 , Diversity)

   Rarely have studies assessed Odonata diversity for the entire Nearctic realm by including Canada, the United States, and Mexico. For the first time, we explored Odonata diversity in this region according to a definition of natural community assemblages and generated species distribution models (SDMs). Species occurrence data were assembled by reviewing databases of specimens held by significant Odonata repositories and through an extensive search of literature references. Species were categorized as forest-dependent or non-forest-dependent, as lentic or lotic-dependent, and according to conservation status. Predicted distributions were stacked for all species across their entire ranges, including areas outside of the Nearctic. Species richness and corrected weighted endemism (CWE) were then calculated for each grid cell. We found a pattern of greater species richness in the eastern portion of the Nearctic, which can be explained by the higher aquatic habitat diversity at micro and macroscales east of the Rocky Mountains, promoting niche partitioning and specialization. In the Nearctic region, the southeastern US has the highest number of endemic species of dragonflies and damselflies; this degree of endemism is likely due to glacial refuges providing a foundation for the evolution of a rich and unique biota. 

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4. Phylogenetic structure of geographical co‐occurrence among New World Triatominae species, vectors of Chagas disease

   https://doi.org/10.1111/jbi.13810  

   Ceccarelli, Soledad ; Justi, Silvia A. ; Rabinovich, Jorge E. ; Diniz Filho, José Alexandre F. ; Villalobos, Fabricio ( March 2020 , Journal of Biogeography)

   The tropical niche conservatism (TNC) hypothesis is one of the most prominent evolutionary hypotheses that has been supported as an explanation for the diversity gradients of several animal taxa, mainly vertebrates. However, the validity of TNC for less‐known taxa such as disease vectors is not clear. Here, we test predictions of TNC in driving the geographical co‐occurrence among triatomine species, vector insects of Chagas disease. We aim to infer the relative effects of ecological and evolutionary processes in determining triatomine species richness at broad spatial scales.

   America.

   Triatominae (Hemiptera: Reduviidae).

   We gathered distributional, phylogenetic and climatic information for 63 triatomine species. We apply the phylogenetic field (PF) framework based on the phylogenetic structure of species co‐occurrences, considering their climatic preferences. We defined PFs of species by estimating the phylogenetic structure of species co‐occurrence within a focal species’ range. Likewise, climatic conditions within focal species’ ranges were defined as their preferred climates. We applied a spatial‐phylogenetic statistical framework to evaluate geographical variation of species’ co‐occurrence and tested the significance of PFs based on biogeographically informed null models.

   Phylogenetic fields of 17 out of 59 triatomine species showed a trend from overdispersed to clustered, coincident with tropical to subtropical–temperate climate. Triatomines co‐occur with more closely related species in temperate areas and more distantly related species in tropical areas. Temperature seasonality was inversely related to the phylogenetic structure of co‐occurrence within species ranges.

   Geographical co‐occurrence among triatomine species revealed a tropical to subtropical–temperate gradient from overdispersed to clustered PFs and a correspondence between the type of climate in which these species are found and their PFs. Phylogenetic structure within triatomine ranges is explained by their evolutionary history. Our study provides a methodological framework to evaluate the New World triatomine geographical co‐occurrence patterns under a phylogenetic perspective and our results make an important contribution to the understanding of the broad‐scale biodiversity patterns in Triatominae.

    

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5. Higher bee abundance, but not pest abundance, in landscapes with more agriculture on a late-flowering legume crop in tropical smallholder farms

   https://doi.org/10.7717/peerj.10732  

   Vogel, Cassandra ; Chunga, Timothy L. ; Sun, Xiaoxuan ; Poveda, Katja ; Steffan-Dewenter, Ingolf ( January 2021 , PeerJ)

   Background Landscape composition is known to affect both beneficial insect and pest communities on crop fields. Landscape composition therefore can impact ecosystem (dis)services provided by insects to crops. Though landscape effects on ecosystem service providers have been studied in large-scale agriculture in temperate regions, there is a lack of representation of tropical smallholder agriculture within this field of study, especially in sub-Sahara Africa. Legume crops can provide important food security and soil improvement benefits to vulnerable agriculturalists. However, legumes are dependent on pollinating insects, particularly bees (Hymenoptera: Apiformes) for production and are vulnerable to pests. We selected 10 pigeon pea (Fabaceae: Cajunus cajan (L.)) fields in Malawi with varying proportions of semi-natural habitat and agricultural area within a 1 km radius to study: (1) how the proportion of semi-natural habitat and agricultural area affects the abundance and richness of bees and abundance of florivorous blister beetles (Coleoptera: Melloidae ), (2) if the proportion of flowers damaged and fruit set difference between open and bagged flowers are correlated with the proportion of semi-natural habitat or agricultural area and (3) if pigeon pea fruit set difference between open and bagged flowers in these landscapes was constrained by pest damage or improved by bee visitation. Methods We performed three, ten-minute, 15 m, transects per field to assess blister beetle abundance and bee abundance and richness. Bees were captured and identified to (morpho)species. We assessed the proportion of flowers damaged by beetles during the flowering period. We performed a pollinator and pest exclusion experiment on 15 plants per field to assess whether fruit set was pollinator limited or constrained by pests. Results In our study, bee abundance was higher in areas with proportionally more agricultural area surrounding the fields. This effect was mostly driven by an increase in honeybees. Bee richness and beetle abundances were not affected by landscape characteristics, nor was flower damage or fruit set difference between bagged and open flowers. We did not observe a positive effect of bee density or richness, nor a negative effect of florivory, on fruit set difference. Discussion In our study area, pigeon pea flowers relatively late—well into the dry season. This could explain why we observe higher densities of bees in areas dominated by agriculture rather than in areas with more semi-natural habitat where resources for bees during this time of the year are scarce. Therefore, late flowering legumes may be an important food resource for bees during a period of scarcity in the seasonal tropics. The differences in patterns between our study and those conducted in temperate regions highlight the need for landscape-scale studies in areas outside the temperate region. 

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