About: Hemileuca is a(n) research topic. Over the lifetime, 42 publication(s) have been published within this topic receiving 782 citation(s). The topic is also known as: Euchronia & Pseudohazis.
TL;DR: The results suggest that reported declines of silk moth populations in New England may be caused by the importation and introduction of C. concinnata, a generalist parasitoid fly introduced repeatedly to North America from 1906 to 1986.
Abstract: Damage to nontarget (native) invertebrates from biological control introductions is rarely docu- mented. We examined the nontarget effects of a generalist parasitoid fly, Compsilura concinnata (Diptera: Tachin- idae), that has been introduced repeatedly to North America from 1906 to 1986 as a biological control agent against 13 pest species. We tested the effect of previously established populations of this fly on two native, nontar- get species of moths (Lepidoptera: Saturniidae), Hyalophora cecropia and Callosamia promethea , in Massachusetts forests. We estimated survivorship curves for newly hatched H. cecropia larvae ( n 5 500), placed five per tree in the field and found no survival beyond the fifth instar. We simultaneously deployed cohorts ( n 5 100) of each of the first three instars to measure the effect of parasitoids during each stage of development. C. concinnata was re- sponsible for 81% of H. cecropia mortality in the first three instars. We deployed semigregarious C. promethea in aggregations of 1-100 larvae in the field and recorded high rates of parasitism by C. concinnata among C. promethea larvae exposed for 6 days (69.8%) and 8 days (65.6%). We discovered a wild population of a third spe- cies of silk moth, the state-listed (threatened) saturniid Hemileuca maia maia , and found that C. concinnata was re- sponsible for 36% ( n 5 50) mortality in the third instar. Our results suggest that reported declines of silk moth populations in New England may be caused by the importation and introduction of C. concinnata .
TL;DR: Investigations showed that the Cryan's buckmoths clearly belong to the Hemileuca maia species group, but they could not be readily distinguished from other members of that group by means of molecular genetic techniques, suggesting recent divergence.
Abstract: Buckmoths (Hemileuca spp.) are day-flying saturniid moths with diverse ecologies and host plants. Populations that feed on Menyanthes trifoliata, known commonly as Cryan's buckmoths, have been found in only a few bogs and fens near eastern Lake Ontario in New York and near Ottawa in Ontario, Canada. Be- cause of their unique ecological traits, geographic isolation from other Hemileuca populations, and the small number of sites they occupy, there ts concern that the Cryan's buckmoth populations are phylogenetically dis- tinct and should be protected. The Cryan's buckmoths have not yet been taxonomically described and do not appear to have clear distinguishing morphological characters. Both molecular genetic traits (allozymes and mitochondrial DNA sequences) and an ecologically based character (host performance) were investigated to determine whether these populations possess fixed diagnostic characters signifying genetic differentiation from other eastern Hemileuca populations. Such differences would merit separate conservation management as an evolutionarily significant unit. Our studies showed that the Cryan's buckmoths clearly belong to the Hemileuca maia species group, but they could not be readily distinguished from other members of that group by means of molecular genetic techniques. There were no fixed differences in alleles or haplotypes distinguish- ing any of the populations or species, suggesting recent divergence. Nonetheless, in the host-plant performance experiment only the Cryan's buckmoth larvae were able to develop on M. trifoUata, a significant difference from other Hemileuca larvae tested. The Cryan's buckmoth appears to be unique in host performance and warrants protection and management as an evolutionarily significant unit. In cases such as this where groups appear to have recently diverged, investigations into ecologically significant traits may provide indica- tors of conservation significance as reliable as molecular genetic markers.
TL;DR: Overall, the existence of different pheromone types in the differentH.
Abstract: The common sheep moth,Hemileuca eglanterina (Boisduval), appears to have at least two distinct pheromone types. Male moths from the population in the San Gabriel Mountains of southern California are attracted optimally to a blend ofE10,Z12-hexadeca-10,12-dien-1-yl acetate (acetate);E10,Z12-hexadeca-10,12-dien-1-ol (alcohol); andE10,Z12-hexadeca-10,12-dienal (aldehyde), whereas males from the population at Robinson Summit, northwest of Ely, Nevada, are attracted to the two-component blend of alcohol and aldehyde. Populations along the eastern edge of the Sierra Nevada Mountains are composed of individuals of both pheromone types and a type intermediate between the two. Antennae from male moths from the different pheromone types give distinctly different electroantennographic responses when challenged with blends of the pheromone components, with San Gabriel Mountains males showing a large response to acetate and lesser responses to alcohol and aldehyde. In contrast, antennae from Robinson Summit males, which are attracted to lures containing only alcohol and aldehyde, exhibit a large response to alcohol, a smaller response to aldehyde, and minimal or no response to acetate. Male moths from the eastern Sierra Nevada Mountains give antennal responses similar to those of either San Gabriel Mountains or Robinson Summit males. However, eastern Sierra populations also contain an intermediate type that does not occur in areas where the major pheromone types do not occur together. This third type may be a hybrid between the two other pheromone types, and it is attracted in approximately equal numbers to synthetic pheromone lures with and without acetate. The antennae of male moths in all populations tested responded toE10,E12-16:Ac, a major pheromone component of the congenerH. nuttalli, which is sympatric with someH. eglanterina populations, and in mostH. eglanterina populations tested, the addition ofE10,E12-16:Ac antagonized responses to otherwise attractive lure blends. Overall, the existence of different pheromone types in the differentH. eglanterina populations may represent a case of reproductive character displacement.
TL;DR: Differences in the indirect effect are discussed in particular relative to the behavior of predators and prey, ratio of predator to prey sizes, and morphology of the hostplants.
Abstract: An indirect effects is defined here as a reduction in prey survivorship as a consequence of a reduction in growth rate of prey due to the presence of a predator that alters prey behavior. A method for partitioning the direct and indirect effects of predators on prey survivorship indicated that predatory wasps (Polistes sp.:. Vespidae) had both direct and indirect negative effects on survivorship of buckmoth caterpillars (Hemileuca lucina: Saturniidae). In a field experiment, the direct and indirect effects together accounted for 61% of the mortality of the caterpillars. A third of this reduction in survivorship due to the wasps was attributed to an indirect effect, due to the decreased growth rate of the caterpillars that moved into the interior of the hostplant to escape from the wasps. In contrast, in another field experiment, although predatory stinkbugs (Podisus maculiventris: Hemiptera) contributed to 56% of the mortality of buckeye caterpillars (Junonia coenia: Nymphalidae), the indirect effect of stinkbugs on buckeye caterpillars only accounted for 2% of the reduction in survivorship of these caterpillars. These differences in the indirect effect are discussed in particular relative to the behavior of predators and prey, ratio of predator to prey sizes, and morphology of the hostplants.
TL;DR: Within the belt infested by the brown-tail, Euproctis chrysorrhea Linn.
Abstract: That certain Lepidopterous larvae possess poisonous hairs or spines is a fact well known to all entomologists. A real knowledge of such species, however, in general relates to such well known forms as Automeris io Fab., Hemileuca maia Drury, or certain of the EucleidA¦ such as the saddle-back, Sibine stimulea Clem. To those within the belt infested by the brown-tail, Euproctis chrysorrhea Linn., the severe urticating properties of the larval spicules of this form are only too familiar. Yet, outside of these few forms, most entomologists consider the Lepidoptera as being harmless so far as any direct effect upon man is concerned.