Diversity, Vertical Stratification and Co-Occurrence Patterns of the Mycetophilid Community among Eastern Hemlock, Tsuga canadensis (L.) Carrière, in the Southern Appalachians

Abstract

Over 400 species of insects have been found in association with eastern hemlock in the southern Appalachians. Eastern hemlock stands provide an ideal habitat for all life stages of mycetophilids. However, the diversity, distribution and co-occurrence patterns of these species throughout the tree canopy are unknown. This study was initiated to evaluate abundance, species richness and species composition within three designated strata in the canopy of eastern hemlock, assess species for vertical stratification patterns, and determine if co-occurrence patterns of mycetophilid species are random or non-random. During this study, 24 species representing 14 genera were identified and evaluated. Mycetophilid abundance, species richness and composition differed among the lower, middle, and upper strata. Unique assemblages were identified in each stratum, indicating vertical stratification. The upper stratum of the canopy had four exclusive species, the middle had six exclusive species, and the lower stratum had nine exclusive species. The co-occurrence pattern of mycetophilid species in the canopy of eastern hemlock was non-random.

Exploring variation in phyllosphere microbial communities across four hemlock species

“…), 24 species of mycetophilids (Coots et al. ), and 47 predatory arthropod families (Hakeem ) have been found associated with eastern hemlock. Psocoptera graze on microepiphytes (fungi, algae, and lichens) and are eaten by predators (Thornton ), while mycetophilids in their larval stage use fleshy fungi (Coots et al.…”

“…Psocoptera graze on microepiphytes (fungi, algae, and lichens) and are eaten by predators (Thornton ), while mycetophilids in their larval stage use fleshy fungi (Coots et al. ). While the significance of these associations is not well understood, these groups constitute an essential component of the food web within the eastern hemlock system.…”

“…, Coots et al. , b). Hemlock forests are currently threatened by an invasive insect, the hemlock woolly adelgid, Adelges tsugae (Hemiptera: Adelgidae; HWA).…”

“…, DeGraaf and Yamasaki ), and arthropod species (Coots et al. , b). Differences in arthropod community structure have been linked to differences in plant genetics (Dungey et al.…”

Evaluation of systemic neonicotinoid insecticides for the management of the Asian citrus psyllid Diaphorina citri on containerized citrus

“…If this level of metabolism holds true for smaller trees, then failure to establish a colony after the parent imidacloprid concentrations have declined below our detection limit may reflect an increase in the concentrations of metabolites. Such an effect is not unprecedented, as sustained (up to 7 years) control of hemlock woolly adelgid, Adelges tsugae (Annand), on eastern hemlock trees by imidacloprid treatments has recently been shown to rely heavily on the presence of both imidacloprid and the imidacloprid‐olefin metabolite, which is 14‐fold more toxic than imidacloprid . In the same way, thiamethoxam efficacy may be enhanced by the presence of clothianidin residues, providing a combined toxic effect after the individual chemicals are no longer within the detection range of the ELISA.…”