Aims:The oases of Baja California Peninsula (BCP) have been proposed as important hotspots of biodiversity that hold an exceptional richness in the middle of desert conditions. We tested the effect of habitat and anthropogenic disturbance on communities of cavity-nesting taxa, with specific emphasis on bees, wasps, and their natural enemies.Methods: In oases of BCP and desert neighbor environments, trap-nesting taxa were evaluated in response to factors affecting the nest abundance, richness, and community structure. We used statistical models to find correlates of nest abundance and patterns of diversity, as well as ecological analyses to determine the effect of habitat and human disturbance on species diversity and community structure.Results: Solar irradiation, distance to a perennial waterbody and relative humidity influenced the presence of nests, number of brood cells, and parasitism. In general, abundance, species richness, and parasitism were higher in oases, especially in those with less human disturbance. Bees did not discriminate between oases and deserts to nest, whereas mud-daubing wasps were more dependent of oases. The degree of anthropogenic disturbance did not affect the occurrence of parasitism, but it had an adverse effect on the parasitism intensity (number of attacked cells). The community structure was more complex and even in oases and low-disturbed sites. The similarity between sites did not exceed 30%, and the proportion of shared species between oases and deserts varied from 2.7% to 26.6%. Main conclusions:The oases of Baja California are functioning as mesic islands in the desert, each oasis hosting a unique community of cavity-nesting taxa. About 65% of the nests and 50% of species occurred exclusively in the oasis. Thus, cavity-nesting species that depend on mesic conditions could be threatened if the oases of BCP disappear in the future. Local conditions in the oases and deserts of the BCP are shaping the community structure. However, large-scale factors such as climate can influence the seasonality and occurrence of species within the community of cavity-nesting dwellers. Since habitat loss and fragmentation can degrade the oases' functionality,

RESUMEN. El objetivo del presente estudio fue evaluar la diversidad de Scolytinae y Platypodinae en cinco localidades de Tabasco de diciembre de 2012 y abril de 2013. Se utilizaron diez trampas de intercepción de vuelo con alcohol etílico como atrayente para recolectar a los insectos en cada sitio. Se recolectaron en total 4,232 especímenes de 62 especies, de las cuales 57 pertenecen a Scolytinae y cinco a Platypodinae. La mayor diversidad de especies se obtuvo en Malpasito (MP) con un valor de H´=2.11 y la menor en Boca del cerro (BC) con un valor de H´=0.78, la mayor riqueza de especies la registró MP con 39 y la mayor abundancia Francisco Rueda (FR) con 1,500 especímenes. Los géneros Hypothenemus y Xyleborus presentaron la mayor riqueza de especies con diez y siete respectivamente. Las especies Premnobius cavipennis Eichhoff, Xyleborus volvulus (Fabricius), Sampsonius dampfi Schedl, Hypothenemus interstitialis (Hopkins) y Corthylus papulans Eichhoff registraron la mayor abundancia con 2,962 especímenes, lo que representa el 69.99% del total. Las especies Cnesinus elegans Blandford, C. gracilis Blandford, Corthylocurus barbatus (Blandford), Chramesus crenatus Wood, H. effeminatus Wood, H. inaequalis Wood, H. columbi Hopkins y M. robustum (Schedl) son nuevos registros para Tabasco. La lista de especies de estos insectos en Tabasco, México continúa creciendo conforme se incrementan los muestreos, lo que sugiere que no ha sido posible recolectar la diversidad real que albergan los ecosistemas del estado.ABSTRACT. The aim of the present study was to evaluate the diversity of Scolytinae and Platypodinae in five localities of Tabasco between December 2012 and April 2013. Ten flight intercept traps were used with ethyl alcohol as an attractant to collect insects in each site. A total of 4,232 specimens were collected from 62 species, of which 57 belong to Scolytinae and five to Platypodinae. The greatest diversity of species was obtained in Malpasito (MP) with a value of H´=2.11 and the lowest in Boca del Cerro (BC) with a value of H´=0.78, the highest species richness was recorded MP with 39 and the highest species abundance Francisco Rueda (FR) with 1,500 specimens. The genera Hypothenemus and Xyleborus presented the highest species richness with 10 and 7 respectively. The species Premnobius cavipennis Eichhoff, Xyleborus volvulus (Fabricius), Sampsonius dampfi Schedl, Hypothenemus interstitialis (Hopkins) and Corthylus papulans Eichhoff showed the highest abundance with 2,962 specimens, representing 69.99% of the total. The especies Cnesinus elegans Blandford, C. gracilis Blandford, Corthylocurus barbatus (Blandford), Chramesus crenatus Wood, H. effeminatus Wood, H. inaequalis Wood, H. columbi Hopkins and M. robustum (Schedl) are new records for Tabasco. The list of species of these insects in Tabasco, México continues to grow as new samples are taken, suggesting that it has not been possible to collect the real diversity supported by the ecosystems of the state.

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Orchid bees are a conspicuous component of the neotropical bee fauna, with a few species reaching the northernmost natural distribution for the group in northwestern continental Mexico. Among them, Euglossa viridissima Friese is here reported for the first time in the Cape Region of the Baja California peninsula, Mexico, where no species of the group have been found previously. These records are presented, their biogeographical implications discussed, and some interpretations of the local factors that influence the bees is presented.

Examination of old Sceliphron jamaicense (Fabr.) nests at 4 localities near the tip of the Baja California peninsula showed levels of brood success (i.e., the fraction of fully provisioned, closed cells producing viable adult offspring) between 24.6% and 58.1% per site. Failure was predominantly at the pupal stage at all localities. Successful cells are commonly reutilized by other solitary wasps, primarily Trypoxylon (Trypargilum) dubium Coville and Chalybion californicum (Sassure, 1867). There is a pronounced clumping tendency in successes and failures among nests.

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In a survey on hemp grown in western Kentucky we found an average of 27.8 CEW larvae per plant. We recorded 45% parasitism of CEW in these fields by two species of tachinid flies, Winthemia rufopicta and Lespesia aletiae. Most parasitized larvae were third to sixth instars at the time of collection. We found up to 22 tachinid eggs per host larva, 89% of which typically bore between 1 and 5 eggs on the thorax. 45.9% of CEW bearing eggs died. The number of tachinid eggs per host was unrelated to host body mass, but both the number of tachinid eggs and caterpillar body mass influenced CEW survival. Larger CEW often survived parasitism and the number of fly eggs was negatively related to survival rate. The emergence of adult flies was positively correlated with the number of eggs, but no influence of the host size was found. High mortality of CEW larvae and the parasitoids developing within them in this system suggests that secondary chemicals (or poor nutrition) of the hemp diet may be negatively affecting host and parasitoid development and influencing their interactions.