Insect Herbivory in MinnesotaTyphaStands

Abstract

Studies were conducted to identify the common phytophagous insects that feed on Typha spp. (cattails) in Minnesota and to quantify the extent of insect herbivory in natural stands. Six lcpidoptcrans and two aphids wcre noted to feed on Typha shoots. The most common herbivorous inscct in natural stands was the miner-borer Archanara oblonga Grt. (Lepidoptcra: Noctuidae). The noctuid Bellura obliqua Walk. was the most common miner-borer in newly planted cultivated stands. Nineteen Typha stands were sampled in midsummer to quantify the extent of inscct herbivory. Overall, about 15 percent of shoots showed some evidence of insect herbivory. Eight percent of damaged shoots had damage to upper leaves attributable to lepidopteran miner-borers (chiefly A . oblonga). Five percent of shoots had stem damage. Less than one percent of shoots wcre damaged by Icaf-chewing insects. Typha latifolia stands were more heavily infested than those of T . angustifolia or T. glauca. Stands located in southern Minnesota were much more heavily infested than those in northeastern Minnesota. Water depth and shoot nitrogen content did not have a significant effect on infestation rate. The majority of infested shoots suffered minor damage (i.e., 120Y0 reduction in leaf area). Much of the damage caused by lepidopteran miner-borers was indirect. Although natural Typha stands and small cultivated plots are occasionally susceptible to heavy infestations of phytophagous insects, it seems unlikely that insect pests would hamper Typha bio-energy production in Minnesota.

Mechanisms of dominance by the invasive hybrid cattail Typha × glauca

“…Penko and Pratt (1987) found little insect herbivory on non-native Typha spp., though muskrats can substantially reduce cattail biomass (Connors et al 2000). The majority of Typha biomass enters detrital pools, with a long standing-dead phase that slows decay (Christensen et al 2009;Kuehn and Suberkropp 1998).…”

“…A notable feature of Typha-dominated areas is high litter biomass. Typha is highly productive, subjected to relatively little herbivory, and slow to decompose (Christensen et al 2009;Freyman 2008;Penko and Pratt 1987).…”

The effects of shoot age on colonization of an emergent macrophyte (Typha latifolia) by macroinvertebrates

“…For primary consumers, food on Typha shoots is represented by the tissue (living or dead) of the plant itself and/or periphyton. The Lepidoptera and Donacia vulgaris have burrowing herbivorous larvae that feed on the living tissue of Typha shoots ( e g Gaevskaya, 1969;Penko & Pratt, 1987;Newman, 1991), and their observed higher biomass on the younger shoots may be due to the greater amount of living tissue. On the other hand, the shredder Lirnizephilus sp.…”

Ecology of Terrestrial Arthropods in Freshwater Wetlands

“…Attempts to quantify impacts of arthropod herbivores on wetland plants point toward moderate effects. In Minnesota Typha stands, insect herbivores only attacked 20% of the plants and consumed only a small proportion of those plants (99). As mentioned above, most wetland grasses support few herbivores.…”