Comparisons of simple linear regressions of diameter on length indicated that females of any given length tend to have a greater diameter than males of the same length. Mean lengths of males and females did not differ significantly at any of the three sites, but females had a significantly greater mean diameter than males at each site. Sex ratios at the three sites were not significantly different from 50:50. Gordius difficilis was found at three locations in Allamakee, Winneshiek, and Fayette counties. difficilis was known from several cold spring-fed habitats in southeastern Minnesota, surveys targeting this species were conducted in similar habitats in northeastern Iowa. Abstract: Two species of horsehair worms (Chordodes morgani and Paragordius varius) have been reported previously from Iowa or its bordering waters, and two species (Gordius difficilis and G.
Here are just some of the animals we found. The fast-flowing water washed the material into the net. The sample was taken by kicking and rolling the rocks upstream of the open net. There was some ribbon weed growing among the rocks. Just a short distance from the shallow pool, the river narrows and runs rapidly across a stretch of small rocks and stones.
A small ‘raft’ of leaf litter was also added to the bucket.Ģ: Rocky riffle sample. By sweeping slowly with a net, a sample of vegetation and other floating material was collected and transferred to a bucket of water collected from the same location. This was taken by stirring up the layer of silt and leaf litter on the bottom in a very slowly running section of the river. Both were from a freshwater section of the Wonboyn River, but they represented two distinct habitats.ġ: Shallow pool sample. We examined two samples collected earlier that day. Shallow sorting trays, paint brushes, forceps, small dishes, magnifying glasses, identification keys, and two microscopes … the stage was set for a serious foray into the identification of aquatic invertebrates.
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