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Pink shrimp, Penaeus duorarum Burkenroad, from natural populations in Biscayne Bay and from cultured populations in ponds operated by the University of Miami at Turkey Point, Florida, were examined for parasites during the summer of 1969. Parasites, with percentage incidence in parentheses, found in pond‐reared shrimp were: the gregarines Cephalolobus penaeus Kruse, 1959 (11%), and Nematopsis penaeus Kruse, 1959 (20%); the larval cestodes Prochristianella penaeus Kruse, 1959 (17%), and Polypocephalus sp. (0.7%). Additional parasites found in wild shrimp but absent in pond‐reared samples were: the microsporidian Thelohania duorara Iversen and Van Meter, 1959 (8%); an unidentified cestode of the genus Prochristianella (14%): and a larval nematode, probably Contracaecum habena (Linton, 1900) (13%). The incidence of parasitism in pond‐reared shrimp is compared to that previously recorded from wild P. duorarum collected from Tortugas and Biscayne Bay. Absence or reduced incidence of certain parasites in pond‐reared P. duorarum is discussed.

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Preliminary experiments indicate that mice inoculated with cercariae of Schistosoma mansoni that have been exposed to cobalt-60 radiation in the range of 2500 to 3000 rep develop immunity to reinfection with nonradiated cercariae.

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Forest managers in many parts of the world are charged with protecting rare lichen species, including species growing near their range limits. Rare lichens may be particularly vulnerable to effects of climate change, and conserving lichen diversity necessitates understanding factors that limit species distributions. Habitat suitability envelopes for lichens are shifting as the climate changes, but it is unclear whether and how local (e.g., within-tree) lichen species distributions will shift. Conserving lichen biodiversity also requires effective field surveys to detect and monitor rare lichen populations. However, the reliability of rare lichen survey methods currently used across global forest lands is rarely tested. In this study, we quantify the canopy distribution of an epiphytic old-growth forest cyanolichen near its southern range limit and test whether ground surveys reliably detect canopy populations. Near its southern range limit, Lobaria oregana was most abundant in two distinct zones within tree crowns: on branches of large trees in the mid-crown, and on boles of small trees near ground level. The abundance of this species near ground level suggests that lichens may benefit from cooler, wetter microclimates near the equatorial edges of their ranges. Maintaining these microclimate habitats may be a key to longterm viability of rear edge lichen populations. Targeted ground surveys reliably detected L. oregana in litterfall underneath trees where it was abundant in the crowns. However, ground surveys did not reliably detect the lichen underneath trees when it occurred in the crowns in low abundance. Our results suggest that ground surveys are useful for characterizing abundant lichen species, but that canopy surveys (e.g., tree climbing) may be needed to reliably detect lichens when they occur at low abundance.

Branches and boles of trees in wet forests are often carpeted with lichens and bryophytes capable of providing periodically saturated habitat suitable for microfauna, animals that include tardigrades, rotifers, nematodes, mites, and springtails. Although resident microfauna likely exhibit habitat preferences structured by fine-scale environmental factors, previous studies rarely report associations between microfaunal communities and habitat type (e.g., communities that develop in lichens vs. bryophytes). Microfaunal communities were examined across three types of epiphyte and three sampling heights to capture gradients of microenvironment. Tardigrades, rotifers, and nematodes were significantly more abundant in bryophytes than fruticose lichen or foliose lichen. Eight tardigrade species and four tardigrade taxa were found, representing two classes, three orders, six families, and eight genera. Tardigrade community composition was significantly different between bryophytes, foliose lichen, fruticose lichen, and sampling heights. We show that microenvironmental factors including epiphyte type and sampling height shape microfaunal communities and may mirror the environmental preferences of their epiphyte hosts.