Biology subjects

McCallum, M. L.

Publications and source records attributed to McCallum, M. L..

6 recordsLinked to original sources

bioRxiv2018

Using fuzzy sets to deal with uncertainty in single-species, single-season occupancy models.

Occupancy modeling is a valuable tool for managing wildlife populations. Current occupancy models provide estimates of occurrence based on a point estimate for the species detectability and presence-absence. However, detectability can vary based on many variables ranging from weather to personnel. Therefore, I propose the use of fuzzy sets rather than point estimates for detectability and binomial presence-absence data during calculations of occupancy. Fuzzy occupancy estimates are easier to determine, more robust, and generally more informative than traditional point-based occupancy models. Consequently, managers will have better information available for comparing occupancy values among sites. Fuzzy sets are especially useful when parameters of the study violate key data standards.

ecology↗

bioRxiv2018

Angular Substrate Preference and Molting Behavior of the Giant River Prawn, Macrobrachium rosenbergii and its Implications for Cannibalism Management

The Giant River Prawn is an important commercial species from southeastern Asia and has a large global market. It has a complex life cycle in which it undergoes several molting sequences. Many arthropods require firm perches on which they can perform ecdysis. We investigated preference for substrate slope and its influence on ecdysis. We discovered that prawns occupy horizontal surfaces more frequently than others, but during pre-molt and molt stages, they shift their habitat use to non-horizontally sloped surfaces. Here, they will flex their shell and later molt. We recommend modification of cannibalism management in commercial facilities by providing sufficient vertical (strongly preferred) or high-sloped (greater than 30 degrees) surfaces to facilitate ecdysis, while providing much horizontal space for foraging and other activities. This should create habitat separation between foraging and highly susceptible freshly-molted prawns, thus leading to reduced cannibalism-related mortality.\n\nFundingThis work was supported by the USDA Evans Allen Program at Langston University, Project Number USDA-NIFA-OKLUMCCALLUM2017.\n\nDisclosure statementWe acknowledge that there is no financial interest or benefit that has arisen from the direct applications of our research.

animal behavior and cognition↗

bioRxiv2018

Will the Illinois chorus frog (Pseudacris streckeri illinoensis) survive in Arkansas? A case study of a secretive species in need of protection

The range of the Illinois chorus frog (Pseudacris streckeri illinoensis) in Arkansas is restricted to the eastern quarter of Clay County. Nearly 100% of this species native sand-prairie habitat has been converted to agricultural fields. The original range of the Illinois chorus frog encompassed at least 9,982 ha. Although two new localities were identified in 2002, the current range is only 4,399 ha in 2002. This represents a 56% range contraction since 1992. Calling was heard in only 44.5% of its original range. This species may be experiencing a severe range contraction. Decay models predict the extirpation of the Illinois chorus frog in Arkansas within 17.5 to 101 yr. Suggested factors contributing to this range contraction may include drought, pesticide use, changes in surface water hydrology, U.S. E.P.A. Best management practices, and this species limited ability to recolonize extirpated sites.

ecology↗

bioRxiv2018

Occurence of lymphedema in wild-caught anurans

Lymphedema is a condition in which the lymph hearts fail to pump fluid from the lymph sacs of anurans and other amphibians. This causes the sacs to fill with fluid and provide the frog with balloon-like swellings or over-all appearance. The condition has previously been connected with various diseases including tadpole edema virus and chytrids. I observed lymphedema in six anuran species (Acris blanchadi*, Anaxyrus fowleri*, Hyla squirrela*, Pseudacris streckeri illinoensis*, Rana sylvatica, Rana sphenocephala* [species with * are species records for lymphedema]).

ecology↗

bioRxiv2018

Mass Mortality of Wood Frogs (Rana sylvatica) in the Ozark National Forest: Is it Acid Rain?

We describe observations of a continuing mass mortality event primarily involving wood frogs, but involving other amphibians to a lesser degree. The investigation took place from Spring 2000 through Spring 2004. No definitive correlations between environmental variables and mortality could be identified. Forensic analysis could not isolate causal pathogens. Although mortality fluctuated during the study, it may have spread to other species. Our report identifies population level problems in the eastern part of the Ozark National Forest but is unable to identify a cause. Future studies that more thoroughly address contaminants, pathogens/parasites, and other potential environmental problems in the Ozark National Forest are warranted.

ecology↗

bioRxiv2018

Life history trade-offs in ectotherms impart a pseudo-hormetic response, not hormesis.

All organisms are faced with survival and fitness challenges. However, differences in how ectotherms and endotherms deal with these challenges causes confusion when theoretical explanations are proposed. Herein, an immunochallenged, immature ectothermic vertebrate increased growth in the face of immunochallenge, reminiscent of up-regulated physiological efficiency termed hormesis. The immunochallenged subjects increased food intake relative to control animals, a largely ignored possibility in previous studies. This likely led to an energy surplus that fueled additional growth. Although there was increased resource demand from the immune response that exceeded internal stores, the acceptably sized food items contained more resources than immunologically-driven demand required. We theorize that because ectotherms lack significant internally-stored resources compared to endotherms, they must feed to fuel increased physiological demand. This can lead to excess resource intake because the minimum acceptably sized prey contains more available resources than upregulation required. This creates a pseudo-hormetic hormetic response, fueled by excess food intake rather than significant improved physiological efficiency. Further, we speculate that lifespan and/or maturity may interact with resource management ectotherms, though our data are inconclusive on this matter. Ultimately, our data suggest additional growth when ectotherms face stressors is a pseudo-hormetic response stemming from increased food intake instead of upregulated physiological efficiency.

evolutionary biology↗