From endogenous to exogenous pattern formation: Invasive plant species changes the spatial distribution of a native ant

Invasive species are a significant threat to global biodiversity, but our understanding of how invasive species impact native communities across space and time remains limited. Based on observations in an old field in Southeast Michigan spanning 35 years, our study documents significant impacts of habitat change, likely driven by the invasion of the shrub, Elaeagnus umbellata, on the nest distribution patterns and population demographics of a native ant species, Formica obscuripes. Landcover change in aerial photographs indicates that E. umbellata expanded aggressively, transforming a large proportion of the original open field into dense shrubland. By comparing the ant’s landcover preferences before and after the invasion, we demonstrate that this species experienced a significant unfavorable change in its foraging areas. We also find that shrub landcover significantly moderates aggression between nests, suggesting nests are more related where there is more E. umbellata. This may represent a shift in reproductive strategy from queen flights, reported in the past, to asexual nest budding. Our results suggest that E. umbellata may affect the spatial distribution of F. obscuripes by shifting the drivers of nest pattern formation from an endogenous process (queen flights), which led to a uniform pattern, to a process that is both endogenous (nest budding) and exogenous (loss of preferred habitat), resulting in a significantly different clustered pattern. The number and sizes of F. obscuripes nests in our study site are projected to decrease in the next 40 years, although further study of this population’s colony structures is needed to understand the extent of this decrease. Elaeagnus umbellata is a common invasive shrub, and similar impacts on native species might occur in its invasive range, or in areas with similar shrub invasions.Invasive species are a threat to global biodiversity, but our understanding of how they impact native communities across space and time remains limited. We compared the spatial distribution of a population of native ant Formica obscuripes in SE Michigan between 1980 and 2015, during which the invasive shrub Elaeagnus umbellata changed the dominant landcover from open field to shrubland. Analyses of ant habitat preference and aggressivity suggest that this landcover change caused the nest pattern formation process to shift from endogenous (reproductive queen flights) that led to a uniform pattern, to both endogenous (nest budding) and exogenous (loss of preferred habitat), resulting in a significantly different clustered pattern. Results of a stage‐structured model suggest that the ant population may be declining. Elaeagnus umbellata is a common invasive shrub, and similar impacts on native species might occur in its invasive range, or in areas with similar shrub invasions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136690/1/gcb13671.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136690/2/gcb13671_am.pd

Comparative Evaluation of Development and Reproductive Capacity of Two Biotypes of Lilioceris cheni (Coleoptera: Chrysomelidae), Biological Control Agents of Air Potato (Dioscorea Bulbifera) in Florida

© The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. A Chinese biotype of Lilioceris cheni Gressitt and Kimoto (Coleoptera: Chrysomelidae) is being mass reared and released in Florida for biological control of the invasive air potato vine, Dioscorea bulbifera L. (Dioscoreales). Another biotype from Nepal is under investigation for determining whether its release would benefit the ongoing biological control program.We compared temperature-dependent development, fecundity, life table parameters, and consumption of the two biotypes in the laboratory. Both biotypes completed development at 20-30 C, although survival of Chinese beetles was higher at 20 C and 27.5 C, and survival of Nepalese beetles was higher at 30 C. In addition, Nepalese beetles developed at a faster rate at 20 C, and consumed air potato foliage at a higher rate at 25 C. The most important difference between the biotypes, with regard to biological control purposes, was the shorter generation time of Nepalese beetles, which resulted in a higher intrinsic rate of population increase, despite much higher fecundity of Chinese beetles. The higher intrinsic rate of increase of the Nepalese beetles may allow a more rapid population increase in the field, and thus, greater damage to air potato plants. However, differences in other life history traits, such as overwintering ability, diapause, and cold tolerance, will also influence field performance

New Species Diversity Revealed from Molecular and Morphological Characterization of Gall-Inducing Calophya

Four populations of Calophya spp. (Hemiptera: Calophyidae) collected in Brazil were characterized using molecular and morphological methods. Examination of adults revealed the presence of 2 morphotypes, which were identified as C. latiforceps and C. terebinthifolii. However, morphological examination of 5th instar nymphs detected differences within C. latiforceps, with a population from Ubu, Espírito Santo, being distinct from the other 2 populations. Molecular characterization of the mitochondrial CO1 gene supported the presence of a new species of Calophya.