Nesting Behavior, Phenology, and Bionomics of the High Andean Leaf-Cutter Bee Megachile (Cressoniella) amparo.

Megachile amparo (González, Revista Colombiana De Entomología 32(1):93-96, 2006) is the only high Andean leaf-cutter bee reported in Colombia and is possibly endemic to the Colombian Andes. Although it is frequently observed, even in urban areas, its biology and ecology remain unknown. The present study aimed to describe detailed aspects of its bionomy. Trap-nests were installed on the Campus of the Nueva Granada University (Cajicá, Colombia) from June/2018 to March/2020. The trap-nests were wooden blocks (25 × 15 × 14 cm) with 30 cavities of Ø = 1 cm and different lengths (50 mm, 75 mm, and 100 mm) lined with waxed paper straws. During the observations, an increasing number of trap-nests were installed, increasing from 250 to 720 cavities. The trap-nests were monitored three times a week, recording both the date the start and end building by female. Most of the nest were maintained in the field to estimate the sex ratio, cell survival, and total development time under natural conditions. Thirty-two nests were removed at different times of the observation period to establish number of cells per nest, and cells built per female per day. We incubated 20 cells from different nests at 18 °C, 22 °C, 26 °C, and 32 °C to estimate the base temperature, thermal constant k (developmental time in degree days), and cell survival. Young cells of different positions were dissected and weighed to characterize food provision and brood cells. Computerized tomography-CT scans were performed in 30 brood cells to determine if diapause occurred during prepupal stage. Females nested 7- and 10-cm-long cavities and the number of cells per nest varied with cavity length. The brood cells had a length of 1.23 ± 0.12 cm and a diameter of 0.92 ± 0.05 cm. The female spends 1.17 ± 0.29 days to build a brood cell. Food provision varied according to the position of the brood cell in the nest. The adults of M. amparo present a marked seasonality being more active during dry months. Base temperature and thermal constant k were different for males and females. The sex ratio is female biased (1.9:1), and cell survival in the field was 89% with no cleptoparasites or predators recorded.

Invasive potential of tropical fruit flies in temperate regions under climate change.

Tropical fruit flies are considered among the most economically important invasive species detected in temperate areas of the United States and the European Union. Detections often trigger quarantine and eradication programs that are conducted without a holistic understanding of the threat posed. Weather-driven physiologically-based demographic models are used to estimate the geographic range, relative abundance, and threat posed by four tropical tephritid fruit flies (Mediterranean fruit fly, melon fly, oriental fruit fly, and Mexican fruit fly) in North and Central America, and the European-Mediterranean region under extant and climate change weather (RCP8.5 and A1B scenarios). Most temperate areas under tropical fruit fly propagule pressure have not been suitable for establishment, but suitability is predicted to increase in some areas with climate change. To meet this ongoing challenge, investments are needed to collect sound biological data to develop mechanistic models to predict the geographic range and relative abundance of these and other invasive species, and to put eradication policies on a scientific basis.

The coffee agroecosystem: bio-economic analysis of coffee berry borer control (Hypothenemus hampei).

Coffee, after petroleum, is the most valuable commodity globally in terms of total value (harvest to coffee cup). Here, our bioeconomic analysis considers the multitude of factors that influence coffee production. The system model used in the analysis incorporates realistic field models based on considerable new field data and models for coffee plant growth and development, the coffee/coffee berry borer (CBB) dynamics in response to coffee berry production and the role of the CBB parasitoids and their interactions in control of CBB. Cultural control of CBB by harvesting, cleanup of abscised fruits, and chemical sprays previously considered are reexamined here to include biopesticides for control of CBB such as entomopathogenic fungi (Beauveria bassiana, Metarhizium anisopliae) and entomopathogenic nematodes (Steinernema sp., Heterorhabditis). The bioeconomic analysis estimates the potential of each control tactic singly and in combination for control of CBB. The analysis explains why frequent intensive harvesting of coffee is by far the most effective and economically viable control practice for reducing CBB infestations in Colombia and Brazil.

Eradication of invasive species: why the biology matters.

Published bi- and tri-trophic physiologically based demographic system models having similar sub components are used to assess prospectively the geographic distributions and relative abundance (a measure of invasiveness) of six invasive herbivorous insect species across the United States and Mexico. The plant hosts and insect species included in the study are: 1) cotton/pink bollworm, 2) a fruit tree host/Mediterranean fruit fly, 3) olive/olive fly, 4) a perennial host/light brown apple moth, 5) grapevine/glassy-winged sharpshooter and its two egg parasitoids, and 6) grapevine/European grapevine moth. All of these species are currently or have been targets for eradication. The goal of the analyses is to predict and explain prospectively the disparate distributions of the six species as a basis for examining eradication or containment efforts against them. The eradication of the new world screwworm is also reviewed in the discussion section because of its pivotal role in the development of the eradication paradigm. The models used are mechanistic descriptions of the weather driven biology of the species. Observed daily weather data (i.e., max-min temperatures, solar radiation) from 1,221 locations across the United States and Mexico for the period 1983-2003 were used to drive the models. Soil moisture and nutrition were assumed nonlimiting. The simulation results were mapped using GRASS GIS. The mathematical underpinnings of the modeling approach are reviewed in the appendix and in the supplemental materials.

A regional analysis of weather mediated competition between a parasitoid and a coccinellid predator of oleander scale.

The regulation of an asexual population of the oleander scale [Aspidiotus nerii Bouchè (Hemiptera: Diaspididae)] on California bay tree [Umbellularia californica (Hopk. & Arn.) Nut.] by two natural enemies; an idiobiont, ectoparasitoid Aphytis chilensis Howard (Hymenoptera: Aphelinidae) and a coccinellid predator (Rhysobius lophanthae (Blaisd.) (Coleoptera: Coccinellidae), was examined using a general weather-driven, tri-trophic, physiologically based age-mass structured demographic model. The model is of intermediate complexity and was parameterized using extensive laboratory data and field observations from Albany, CA. Temperature-dependent physiological indices were estimated from the laboratory data and used to scale per capita growth, fecundity and survivorship rates from maximal values in a time varying environment. The tri-trophic model was integrated in a GIS (geographic information system) and the species dynamics examined across years and across the ecological zones of California. Field data and simulation results suggested the coccinellid predator was the most important regulating agent of oleander scale in the mild climate of Albany. However, multiple linear regression analysis of simulation data across all ecological zones of California shows that the parasitoid A. chilensis is the most important agent in suppressing oleander scale densities in warmer climates, while the predator R. lophanthae increases scale density an average of 9.7% across all regions.

A regional analysis of weather mediated competition between a parasitoid and a coccinellid predator of oleander scale

The regulation of an asexual population of the oleander scale [Aspidiotus nerii Bouchè (Hemiptera: Diaspididae)] on California bay tree [Umbellularia californica (Hopk. & Arn.) Nut.] by two natural enemies; an idiobiont, ectoparasitoid Aphytis chilensis Howard (Hymenoptera: Aphelinidae) and a coccinellid predator (Rhysobius lophanthae (Blaisd.) (Coleoptera: Coccinellidae), was examined using a general weather-driven, tri-trophic, physiologically based age-mass structured demographic model. The model is of intermediate complexity and was parameterized using extensive laboratory data and field observations from Albany, CA. Temperature-dependent physiological indices were estimated from the laboratory data and used to scale per capita growth, fecundity and survivorship rates from maximal values in a time varying environment. The tri-trophic model was integrated in a GIS (geographic information system) and the species dynamics examined across years and across the ecological zones of California. Field data and simulation results suggested the coccinellid predator was the most important regulating agent of oleander scale in the mild climate of Albany. However, multiple linear regression analysis of simulation data across all ecological zones of California shows that the parasitoid A. chilensis is the most important agent in suppressing oleander scale densities in warmer climates, while the predator R. lophanthae increases scale density an average of 9.7 percent across all regions.

O controle natural de uma população assexuada de cochonilha-da-espirradeira (Aspidiotus nerii Bouchè (Hemiptera: Diaspididae) em plantas do louro da California [Umbellularia californica (Hopk. & Arn.) Nut.] por dois de seus inimigos naturais [Aphytis chilensis Howard (Hymenoptera: Aphelinidae) e Rhysobius lophanthae (Blaisd.) (Coleoptera: Coccinellidae)] foi examinado em meio-ambiente com mudanças climáticas usando um modelo geral tritrófico, com base em estrutura populacional de idade e massa e acionado por condições climáticas. O modelo é de complexidade intermediária e os parâmetros foram obtidos através de extensas observações de laboratório e campo em Albany, Califórnia. índices fisiológicos dependentes de temperatura foram desenvolvidos a partir de dados de laboratório e usados para modificar o crescimento per capita, fecundidade e taxas de sobrevivência dos valores máximos. O modelo tritrófico foi integrado em GIS (sistema geográfico de informação ) e a dinâmica das espécies foi examinada através dos anos e das zonas ecológicas da Califórnia. Dados de campo e resultados de modelagem sugerem que o coccinelídeo predador é o agente mais importante no controle da cochonilha-da-espirradeira no clima ameno de Albany. Entretanto, a análise de regressão linear multivariada de dados de simulações regionais, demonstra que, sob altas temperaturas, A. chilensis é o fator mais importante suprimindo as densidades da cochonilha, enquanto o predador R. lophanthae é mais eficiente em regiões mais frias. A presença de R. lophanthae aumenta a densidade da cochonilha 9,7 por cento em média através das zonas ecológicas da Califórnia.