The Current Status of the Distribution Range of the Western Pine Beetle, Dendroctonus brevicomis (Curculionidae: Solytinae) in Northern Mexico.

The distribution range of the western pine beetle Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae) is supported only by scattered records in the northern parts of Mexico, suggesting that its populations may be marginal and rare in this region. In this study, we review the geographical distribution of D. brevicomis in northern Mexico and perform a geometric morphometric analysis of seminal rod shape to evaluate its reliability for identifying this species with respect to other members of the Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae) complex. Our results provide 30 new records, with 26 distributed in the Sierra Madre Occidental and 4 in the Sierra Madre Oriental. These records extend the known distribution range of D. brevicomis to Durango and Tamaulipas states in northern Mexico. Furthermore, we find high geographic variation in size and shape of the seminal rod, with conspicous differences among individuals from different geographical regions, namely west and east of the Great Basin and between mountain systems in Mexico.

Beetle diversity in fragmented thornscrub and isolated trees / Diversidade de coleópteros em um fragmento do bioma thornscrub e árvores isoladas

Abstract Due to land use change mainly for induced agriculture, Tamaulipan thornscrubin northeast Mexico has been cleared and transformed into small patches of vegetation as small as isolated trees surrounded by agricultural fields. In this study, we explored how tree isolation or growing inside a fragment of remnant vegetation influence diversity of coleopterans in two plant species (Prosopis laevigata (Humb. &Bonpl.exWilld.) M.C. Johnst. (mesquite) and Ebenopsis ebano (Berl.) Barneby (Texas ebony). We found 72 coleopteran morphospecies; fifteen occurred mainly in remnant fragments and ten mainly in isolated trees. There were more insects under isolated mesquites than under those immersed in remnant fragments, while in Texas ebony the highest beetle density for isolated trees coincided with periods of bean and maize in surrounding agriculture.

Resumo Devido a mudança de uso da terra para induzir principalmente a agricultura, o bioma thornscrub no nordeste México tem sido transformado em fragmentos pequenos como árvores isoladas rodeadas por campos agrícolas. Neste estudo exploramos como o isolamento das árvores influi na diversidade de coleópteros em duas espécies de plantas (Prosopis laevigata (Humb. & Bonpl.ex Willd) M.C. Johnst. (mesquite) e Ebenopsis ebano (Berl.) Barneby (Texas ebony). Encontramos 72 morfospecies do coleópteros; quinze ocorreram principalmente em fragmentos remanescentes e dez em árvores isoladas. No estudo houve mais insetos nas “mesquite” isoladas do que nos fragmentos remanescentes do bioma thornscrub, enquanto que em “Texas ebony” a densidade alta de coleópteros para árvores isoladas coincidiu com períodos de produção de feijão e milho na agricultura ao redor.

Beetle diversity in fragmented thornscrub and isolated trees.

Due to land use change mainly for induced agriculture, Tamaulipan thornscrubin northeast Mexico has been cleared and transformed into small patches of vegetation as small as isolated trees surrounded by agricultural fields. In this study, we explored how tree isolation or growing inside a fragment of remnant vegetation influence diversity of coleopterans in two plant species (Prosopis laevigata (Humb. &Bonpl.exWilld.) M.C. Johnst. (mesquite) and Ebenopsis ebano (Berl.) Barneby (Texas ebony). We found 72 coleopteran morphospecies; fifteen occurred mainly in remnant fragments and ten mainly in isolated trees. There were more insects under isolated mesquites than under those immersed in remnant fragments, while in Texas ebony the highest beetle density for isolated trees coincided with periods of bean and maize in surrounding agriculture.