The eastern population of the North American monarch butterfly (Danaus plexippus) overwinters fro... more The eastern population of the North American monarch butterfly (Danaus plexippus) overwinters from November through March in the high-altitude (3000 m+) forests of central Mexico during which time they rely largely on stored lipids. These are acquired during larval development and the conversion of sugars from floral nectar by adults. We sampled fall migrant monarchs from southern Canada through the migratory route to two overwintering sites in 2019 (n = 10 locations), 2020 (n = 8 locations) and 2021 (n = 7 locations). Moderate to extreme droughts along the migratory route were expected to result in low lipid levels in overwintering monarchs but our analysis of lipid levels of monarchs collected at overwintering sites indicated that in all years most had high levels of lipids prior to winter. Clearly, a significant proportion of lipids were consistently acquired in Mexico during the last portion of the migration. Drought conditions in Oklahoma, Texas and northern Mexico in 2019 resu...
The monarch butterfly (<i>Danaus plexippus</i>) population in North America has sharp... more The monarch butterfly (<i>Danaus plexippus</i>) population in North America has sharply declined over the last two decades. Despite rising concern over the monarch butterfly's status, no comprehensive study of the factors driving this decline has been conducted. Using partial least-squares regressions and time-series analysis, we investigated climatic and habitat-related factors influencing monarch population size from 1993 to 2014. Potential threats included climatic factors, habitat loss (milkweed and overwinter forest), disease and agricultural insecticide use (neonicotinoids). While climatic factors, principally breeding season temperature, were important determinants of annual variation in abundance, our results indicated strong negative relationships between population size and habitat loss variables, principally glyphosate use, but also weaker negative effects from the loss of overwinter forest and breeding season use of neonicotinoids. Further declines in population size because of glyphosate application are not expected. Thus, if remaining threats to habitat are mitigated we expect climate-induced stochastic variation of the eastern migratory population of monarch butterfly around a relatively stationary population size.
... USA. All drones were removed from W, O and G apiaries, and young cordovan drones and brood we... more ... USA. All drones were removed from W, O and G apiaries, and young cordovan drones and brood were added to additional nuclei at Y. Young, marked, wild-type drones were located similarly at B. Virgin queens (>6 days) ho... ...
Annals of The Entomological Society of America, May 15, 1967
... ORLEY R. TAYLOR, JR. ... The duration of each copulation was not determined and these 3 copul... more ... ORLEY R. TAYLOR, JR. ... The duration of each copulation was not determined and these 3 copulations may have been of insufficient length to permit completion of the mating sequence. Of the infertile females, 28 were set up with another male; 19 (67.8%) mated. ...
... Although the methods utilized and the data collected do not completely warrant his conclusion... more ... Although the methods utilized and the data collected do not completely warrant his conclusions, Darchen (1973) stated that African bees in Gabon showed less ability to control temperature in their nest than European bees in Israel. Nunez (1979) found that ...
The eastern population of the North American monarch butterfly (Danaus plexippus) overwinters fro... more The eastern population of the North American monarch butterfly (Danaus plexippus) overwinters from November through March in the high-altitude (3000 m+) forests of central Mexico during which time they rely largely on stored lipids. These are acquired during larval development and the conversion of sugars from floral nectar by adults. We sampled fall migrant monarchs from southern Canada through the migratory route to two overwintering sites in 2019 (n = 10 locations), 2020 (n = 8 locations) and 2021 (n = 7 locations). Moderate to extreme droughts along the migratory route were expected to result in low lipid levels in overwintering monarchs but our analysis of lipid levels of monarchs collected at overwintering sites indicated that in all years most had high levels of lipids prior to winter. Clearly, a significant proportion of lipids were consistently acquired in Mexico during the last portion of the migration. Drought conditions in Oklahoma, Texas and northern Mexico in 2019 resu...
The monarch butterfly (<i>Danaus plexippus</i>) population in North America has sharp... more The monarch butterfly (<i>Danaus plexippus</i>) population in North America has sharply declined over the last two decades. Despite rising concern over the monarch butterfly's status, no comprehensive study of the factors driving this decline has been conducted. Using partial least-squares regressions and time-series analysis, we investigated climatic and habitat-related factors influencing monarch population size from 1993 to 2014. Potential threats included climatic factors, habitat loss (milkweed and overwinter forest), disease and agricultural insecticide use (neonicotinoids). While climatic factors, principally breeding season temperature, were important determinants of annual variation in abundance, our results indicated strong negative relationships between population size and habitat loss variables, principally glyphosate use, but also weaker negative effects from the loss of overwinter forest and breeding season use of neonicotinoids. Further declines in population size because of glyphosate application are not expected. Thus, if remaining threats to habitat are mitigated we expect climate-induced stochastic variation of the eastern migratory population of monarch butterfly around a relatively stationary population size.
... USA. All drones were removed from W, O and G apiaries, and young cordovan drones and brood we... more ... USA. All drones were removed from W, O and G apiaries, and young cordovan drones and brood were added to additional nuclei at Y. Young, marked, wild-type drones were located similarly at B. Virgin queens (>6 days) ho... ...
Annals of The Entomological Society of America, May 15, 1967
... ORLEY R. TAYLOR, JR. ... The duration of each copulation was not determined and these 3 copul... more ... ORLEY R. TAYLOR, JR. ... The duration of each copulation was not determined and these 3 copulations may have been of insufficient length to permit completion of the mating sequence. Of the infertile females, 28 were set up with another male; 19 (67.8%) mated. ...
... Although the methods utilized and the data collected do not completely warrant his conclusion... more ... Although the methods utilized and the data collected do not completely warrant his conclusions, Darchen (1973) stated that African bees in Gabon showed less ability to control temperature in their nest than European bees in Israel. Nunez (1979) found that ...
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