An isolate of the soil fungus Scopulariopsis brevicaulis was identified from the surface of female winter ticks (Dermacentor albipictus) collected from recently dead moose (Alces alces) calves in New Hampshire in the northeastern United States. It was the sole isolate, and it matched with 98% nucITS similarity (molecular systematics Blast match) to S. brevicaulis species from soil and other tick species. Inoculation of tick larvae and eggs with 108 spores/mL + 0.05% Tween (aqueous inoculum) resulted in mortality, reduced survival time, and recovery of S. brevicaulis from within tick tissues. Rapid water loss and death from dehydration were the pathogenic consequences of the fungal infection. Three entomopathogenic fungal isolates from laboratory culture (Beauveria bassiana, B. caledonica, and Metarhizium anisopliae) inoculated concurrently at the same dose, were slightly less pathogenic to eggs than larvae of winter ticks. We conclude that S. brevicaulis imposes a limitation on the freeliving stages of the winter tick population in specific environmental conditions, but commercial fungal treatments as used in local situations to control ticks, are impractical as a means of controlling winter tick density across moose habitats.

We report factors that are limiting for Ascosphaera apis growth: water activity (a w ) and temperature. Features of A. apis were a high water activity, 0.85–0.90 a w at 25/30 °C and 0.90–0.95 a w at 35 °C. A minimum water activity of 0.95 a w was required to produce spores. None of these characteristics changed from cycling or descending/ascending between low and high water activity media. Growth rates varied between isolates. This new study provides the biological data for monitoring and early prediction of disease outbreaks. Beekeepers should note that A. apis has a high water activity for spore production. Healthy bees that keep the internal brood area hot and dry can critically limit incidence of infection and transmission via spores.

We report that larvae of Dermacentor albipictus can detect CO2 from a dry ice source at distances up to 3.0 m and initiate increased activation, movement and questing behaviour. The maximum distance that larvae spread was similar to 0.5 m after 24 h, compared to < 0.1 m without CO2 as an excitant. In Petri dish bioassays, 2,6-dichlorophenol, methyl salicylate and o-nitrophenol acted as attractants, albeit with mixed results at 1.0 m, 2.0 m and 3.0 m, respectively. The 2,6-dichlorophenol target was the most effective, although few larvae crawled > 1.0 m and CO2 was required as a carrier. In Petri dish bioassays, larvae arrested into dense aggregations on eggshells collected after hatching. This arrestment was associated with the eggshell lipids cholesteryl oleate and cholesteryl palmitate, implying that cholesteryl esters act as assembly pheromones for larvae. Faster response was evident at 65% relative humidity (RH) versus 95% RH. Larvae were not arrested by tick excreta, guanine or related purines. Although larvae can be activated from long distances, in the field they remain fairly localized around the egg mass (hatching location), have limited dispersal and are more responsive in drier conditions. Given their arrestant properties, cholesteryl oleate and cholesteryl palmitate may prove useful in pheromone-assisted control methods because D. albipictus larvae are the single stage of infestation to the host.

Ticks utilize a variety of strategies to mitigate water loss and enhance their off-host survival. This is the first report of a primarily tropical zone tick, the Gulf Coast tick Amblyomma maculatum, vector of Rickettsia parkeri, to regulate water loss by photoperiodic induction. Under short-day conditions (10h:14h L:D), water loss rates are decreased. This has a positive effect on survival by extending the time it takes to reach the dehydration tolerance limit. When cycled between long- and short-day conditions, the water loss rate drops and then returns to a faster rate after re-entering long-day conditions; this can occur quickly (within a day), multiple times, and in more than one life history stage. The decrease in water loss is more pronounced in immatures than adults. The percentage body water content, dehydration tolerance limit and critical equilibrium humidity are independent of photoperiodic changes. We conclude that any nonfed stage is adapted for survival by enhanced water conservation when the day length shortens.

To explore how the one-host tick Dermacentor albipictus survives off-host, we determined water balance characteristics of eggs and larvae. In contrast to eggs, larvae lost water fast, absorbed water vapour and died from a low amount of water loss. Placing mated females under near water-saturated conditions yielded larvae that absorbed and survived only at high relative humidities. We observed larvae forming clusters. Water loss rate of larvae decreased as group size increased. In response to day length, larvae lost water slower under long day than short day conditions. Larvae could switch quickly between fast water loss rate (short day) and slow water loss rate (long day) within a day, independent of the photoperiodic experience of the egg or mother. Long day exposure had no effect on water relations, incubation and survival of eggs. We conclude that eggs are modified for water conservation. Larvae survive by having a water balance maternal effect; i.e. capacity for water vapour absorption in the larva is determined by the relative humidity experienced by the mother. Larvae regulate water loss behaviourally through larval clustering and summer quiescence. Understanding these water balance attributes and effects of desiccation on egg and larval survival during summer are important to better predict the potential population impacts of winter ticks on moose.

We report behavioral regulation of body water content in caddisfly larvae, Hydropsyche morosa and Cheumatopsyche pettiti, by selecting microhabitats with different water flow rates. The purpose of our study was to examine features necessary for survival in the same apparent habitat, because the two species co-exist in riffle areas of freshwater streams. Both species are highly sensitive to water loss as a result of high water loss rates and depend on immersion in fresh water (hypo-osmotic) to maintain water stores. In contrast to C. pettiti, H. morosa is larger, retains water more effectively, and features reduced water loss rates with suppressed activation energies. When H. morosa was confined to areas of low or no water flow, overhydration led to rapid mortality, whereas the same conditions favored water balance maintenance and survival in C. pettiti. In attraction bioassays, H. morosa moved and remained within areas of high water flow and C. pettiti preferred areas with low water flow. Because water flow rates are unlikely to directly impact water gain, the mechanism responsible for increased survival and water balance maintenance is likely related to the impact of water flow on oxygen availability, differences in feeding ecology, or other underlying factors.

To examine how aggregation by hairworms may enhance survival in freshwater, we determined water balance characteristics of Paragordius varius in groups of different sizes. P. varius is hyperosmotic resulting in high body water content and functions down to one-half of water stores. Absence of a critical transition temperature implies a watertight, low-porosity cuticle. Aggregated worms lose water slowly, as a physiological consequence of reduced motor activity. The water balance strategy shifts from a reliance on high dehydration tolerance for isolated individuals, affording high water loss rates, to suppressed activation energy when aggregated, wherein blocking water gain is important when water loss is slower. Low water loss rate derives from stillness and aggregating that facilitate mating or anti-predator defense, rather than as a behavior to regulate water loss. Presence of hairworms in streams is an indicator of high-quality water that is necessary to maintain water balance.

This is the first report that adult cave beetles Darlingtonea kentuckensis carry the fungus Beauveria caledonica . This fungus was isolated from dead beetles, collected from the Garbage Pit entrance in Sloans Cave in south-central Kentucky (Pulaski County), USA. The beetles were collected in late September, from soil and guano mixtures that were on the ground nearby ceiling roosts of cave crickets, Hadenoecus spp, in the twilight zone. Beauveria caledonica was the largest single fungal component, comprising 46% of the beetle mycoflora: 31/67 total body isolates from n = 6 beetles. Fungus identification was based on 99% ITS Blast match to other B . caledonica strains (Rehner et al. 2011). An isolate of this fungus is deposited at University of Alberta Microfungus Collection and Herbarium (UAMH), Toronto, Canada. The isolate is listed as B . caledonica strain UAMH 11912. Other components of the beetle mycoflora consisted of 16% Aspergillus (11/67 isolates), 10% Penicillium (7/67 isolates), 10% Mucor (7/67 isolates), 6% Mortierella (4/67 isolates), 3% Cladosporium (2/67 isolates), and 8% unidentified (5/67 isolates) that failed to yield identifiable spore characteristics. Keith Philips identified the beetles, and vouchers are at the Department of Biology, Western Kentucky University, Bowling Green, Kentucky, USA (supporting references: Barr 1979; Boyd 2015).

1 Department of Biology, Wittenberg University, Springfield, Ohio 45501, USA 2 jyoder@wittenberg.edu 3 Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221 USA joshua.benoit@uc.edu (corresponding author) 4 hhobbs@wittenberg.edu 5 nelsonb@wittenberg.edu 6 mainl@wittenberg.edu 7 University of Alberta Microfungus Collection and Herbarium, Devonian Botanic Garden, T6G 2E1, Edmonton, Alberta, Canada, cgibas@ualbera.ca