Landscape Factors Associated with Subterranean Termite (Isoptera: Rhinotermitidae) Treatments and Colony Structure in Residential Subdivisions

Subterranean termites (Isoptera: Reticulitermes) are common structural pests, but it is not well known how landscape factors are associated with urban colonization. This study examined patterns of subterranean termite colonization in 13 mid-Missouri residential subdivisions. Ten- and 20-year-old homes built on historically agricultural and forested landscapes were inspected for treatment by termiticide application or bait stations. Contemporary and historical aerial imagery were analyzed using GIS software, and patterns of colonization were compared among subdivisions. The genetic structure of termite colonies collected in undeveloped landscapes and residential subdivisions was compared using microsatellite DNA. Twenty-year-old subdivisions had significantly higher treatment proportions than 10-year-old subdivisions. At year 10, historically forested subdivisions had a higher treatment proportion than historically agricultural subdivisions. By year 20, there was no significant difference in treatment proportion between historical landscape types, indicating that subdivisions built on agricultural landscapes eventually catch up to subdivisions built on forest landscapes. Although there was not strong statistical support, treated homes in historically agricultural subdivisions tended to be close to forest patches, but there was less of an association in historically forested subdivisions. Colonies in undeveloped landscapes were more inbred compared to colonies in residential subdivisions, indicating that colonies sampled in subdivisions had fewer secondary reproductive and were potentially younger than those sampled in undeveloped landscapes. This study provides some correlative support for the role of dispersing alates as urban colonizers, because treatments were often located at relatively long distances from undisturbed forest patches in historically agricultural subdivisions

Historical landscape interactions and patterns of invasion by subterranean termites (Isoptera: Reticulitermes) in subdivisions of different ages

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The subterranean termite genus Reticulitermes includes some of the most economically destructive termites in the United States, where it is estimated that costs associated with prevention and control may reach $11 billion annually. Despite their economic importance, there are large gaps in our understanding of subterranean termite ecology, due to their cryptic nature and the inherent difficulties of studying subterranean activity. In Missouri, subterranean termite communities differ between undeveloped forested and urban landscapes. Reticulitermes hageni Banks occurs in greater proportions than other subterranean termite species in forested landscapes, while Reticulitermes flavipes (Kollar) occurs in greater proportions than other subterranean termite species in urban landscapes. Thus, it appears that subterranean termite communities change as landscapes are converted from undeveloped to urban. It is not known, however, when Reticulitermes communities change in response to urbanization, or how termite populations invade subdivisions in an altered urban landscape. It is possible that resident subterranean termite populations are eliminated when soils are graded to prepare subdivision sites for construction. It also seems likely that colonies may respond to changing moisture and temperature regimes, or new biotic associations that accompany anthropogenic disturbances and altered landscapes. The purpose of this research is to examine how landscape factors are associated with subterranean termite communities and patterns of invasion as subdivisions are constructed and age over time. Subterranean termites were collected from 25 areas in Columbia, Missouri that were classified along a gradient of urbanization to include 1) undeveloped landscapes; 2) anthropogenically disturbed landscapes; 3) 10-year-old subdivisions; and 4) 20-year-old subdivisions. Subterranean termite communities were assessed by identifying species using PCR-based restriction fragment length polymorphisms (PCR-RFLP). Because secondary reproductiveIncludes bibliographical references (pages 240-258)

Landscape Factors Associated with Subterranean Termite (Isoptera: Rhinotermitidae) Treatments and Colony Structure in Residential Subdivisions

Subterranean termites (Isoptera: Reticulitermes) are common structural pests, but it is not well known how landscape factors are associated with urban colonization. This study examined patterns of subterranean termite colonization in 13 mid-Missouri residential subdivisions. Ten- and 20-year-old homes built on historically agricultural and forested landscapes were inspected for treatment by termiticide application or bait stations. Contemporary and historical aerial imagery were analyzed using GIS software, and patterns of colonization were compared among subdivisions. The genetic structure of termite colonies collected in undeveloped landscapes and residential subdivisions was compared using microsatellite DNA. Twenty-year-old subdivisions had significantly higher treatment proportions than 10-year-old subdivisions. At year 10, historically forested subdivisions had a higher treatment proportion than historically agricultural subdivisions. By year 20, there was no significant difference in treatment proportion between historical landscape types, indicating that subdivisions built on agricultural landscapes eventually catch up to subdivisions built on forest landscapes. Although there was not strong statistical support, treated homes in historically agricultural subdivisions tended to be close to forest patches, but there was less of an association in historically forested subdivisions. Colonies in undeveloped landscapes were more inbred compared to colonies in residential subdivisions, indicating that colonies sampled in subdivisions had fewer secondary reproductive and were potentially younger than those sampled in undeveloped landscapes. This study provides some correlative support for the role of dispersing alates as urban colonizers, because treatments were often located at relatively long distances from undisturbed forest patches in historically agricultural subdivisions

Indigenous arthropod natural enemies of the invasive brown marmorated stink bug in North America and Europe

Since the establishment of the brown marmorated stink bug, Halyomorpha halys (St\ue5l) (Hemiptera: Pentatomidae) in North America and Europe, there has been a large, multi-group effort to characterize the composition and impact of the indigenous community of arthropod natural enemies attacking this invasive pest. In this review, we combine 98 indigenous natural enemy datasets spanning a variety of sampling methods, habitats, and geographic areas. To date, the vast majority of H. halys biological control research has focused on the egg stage, using sentinel egg masses to characterize indigenous parasitoid and predator communities and their contribution to H. halys egg mortality. Although egg parasitism and predation levels by indigenous natural enemies are low (typically <10% each) in most surveys, total egg mortality attributable to natural enemies can be higher (typically between 5 and 25%; up to 83%)\u2014even though these values were likely underestimated in most cases because some mortality due to biological control was not recognized. In North America, where the most data are available, it appears that the relative prevalence of different indigenous parasitoid species varies among habitat types, particularly between crop and non-crop habitats. Predator species responsible for egg mortality are much less commonly identified, but appear to include a wide variety of generalist chewing and sucking predators. To date, studies of natural enemies attacking H. halys nymphs and adults are relatively rare. Based on our review, we identify a number of key research gaps and suggest several directions for future research