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McPherson, KS, United States

McPherson College is a four-year liberal arts college in McPherson, Kansas, United States. It was chartered in 1887 by the leaders of the Church of the Brethren. The college provides a career-oriented liberal arts education. It is accredited by The Higher Learning Commission and is a member of the North Central Association. Wikipedia.

Wilgers D.J.,University of Nebraska - Lincoln | Wilgers D.J.,McPherson College | Wickwire D.,University of Nebraska - Lincoln | Hebets E.A.,University of Nebraska - Lincoln

Males of the wolf spider, Rabidosa punctulata, exhibit condition-dependent alternative mating tactics, whereby small, poor condition males engage in multimodal courtship while large, good condition males adopt a direct mount tactic that forgoes courtship. This study explores the possibility that tactic-specific costs can help explain this unintuitive pattern of mating tactic expression. Specifically, we hypothesize that courtship signaling is costly with respect to eavesdropping by predators and that males can alter their tactic expression based upon the perceived environmental predation risk. We test this by first examining the risk of predation associated with different mating tactics. We use a co-occurring predatory heterospecific, R. rabida as our predator. We found support for the prediction that courting R. punctulata males tended to be attacked more often than non-courting males, and the likelihood of being attacked was best predicted by courtship activity. Given this documented cost, we hypothesized that R. punctulata males would adjust their mating tactic based upon perceived predation risk. In a second experiment, we manipulated perceived predation risk by providing R. punctulata males with different female silk cues (conspecific; predatory heterospecific; conspecific + predatory heterospecific) and examined mating tactic expression. In support of our hypothesis, males were more likely to adopt the direct mount tactic in the presence of predatory heterospecific or mixed silk cues and were more likely to court in the presence of conspecific cues. These results support the hypothesis that the cost of predation from eavesdroppers may influence the evolution and expression of male alternative mating tactics in R. punctulata. © 2014 Koninklijke Brill NV, Leiden. Source

Gaige A.R.,Wichita State University | Ayella A.,McPherson College | Shuai B.,Wichita State University
Physiological and Molecular Plant Pathology

The soil-borne necrotrophic fungal pathogen Macrophomina phaseolina causes charcoal rot disease in many plant species. There are no effective control methods for this disease and no resistant host cultivar for M. phaseolina has been identified. Moreover, the host-pathogen interaction has not been investigated previously at the molecular level. In this study, we established a pathosystem for charcoal rot disease using the model legume Medicago truncatula. Using quantitative real-time PCR, we analyzed the expression of selected M. truncatula genes in response to M. phaseolina infection. Genes involved in flavonoid and isoflavonoid biosynthesis were strongly up-regulated in the shoot; however, activation of these genes in the root was not as dramatic. In addition, some genes in jasmonates (JAs) or ethylene (ET) pathways were not strongly induced in infected root tissue. Treating plants with methyl jasmonate (MJ) or ET induced partial resistance in M. truncatula plants. These results indicate that modifying JA/ET signalling pathways may improve plant resistance to M. phaseolina infection. This study provides a basis for further investigation of the molecular interactions between M. Phaseolina and its plant hosts. © 2010 . Source

Wilgers D.J.,University of Nebraska - Lincoln | Wilgers D.J.,McPherson College | Hebets E.A.,University of Nebraska - Lincoln
Behavioral Ecology and Sociobiology

Female mating behaviors are known to be sensitive to a variety of individual factors both external and internal to a female; however, mating decisions are likely due to a suite of interacting factors. By independently manipulating female and male diet in the wolf spider Rabidosa rabida and testing females across age groups, we demonstrate that, in addition to its independent effect, female nutritional condition interacts with female age to influence female mating behavior. Overall, high-quantity diet (HD) females were more likely to mate than low-quantity diet (LD) females. Within the LD females, older individuals were more likely to mate than younger individuals, while within HD females, mating probabilities were equal across females of different age classes. With respect to mate choice, only female age influenced the likelihood of mating based on male diet. Young females were choosier as they were more likely to mate with HD males than LD males; in contrast, older females were equally likely to copulate with males of each diet treatment. In addition, the likelihood of pre-sexual cannibalism was dependent on both female and male diet. High-quantity diet females were more likely to cannibalize than LD females, and attacks were directed towards LD males most often. We discuss our results in terms of costs versus benefits of female mate choice. © 2011 Springer-Verlag. Source

Hebets E.A.,University of Nebraska - Lincoln | Hansen M.,University of Nebraska - Lincoln | Jones T.C.,East Tennessee State University | Wilgers D.J.,University of Nebraska - Lincoln | Wilgers D.J.,McPherson College
Animal Behaviour

In the wolf spider Rabidosa punctulata, upon encountering a female, males use one of two distinct strategies: (1) they court the female in an attempt to elicit a mating, or (2) they engage in a direct-mount tactic that involves extensive grappling with the female until a mating is achieved. The latter tactic appears more sexually aggressive, and both tactics come with the risk of being cannibalized. We explored the physiological mechanisms underlying this behavioural variation by assessing the relationship between circulating levels of the biogenic amine octopamine (OA), a neuromodulator suggested to play a role in 'fight or flight' responses of arthropods and male mating tactic expression. We predicted, and found support for, a relationship between OA levels and tactic expression, with males adopting the direct-mount tactic expressing higher OA levels than courting males. Male mating tactic and mass also showed a significant interaction, with a negative trend in direct-mounting males and no relationship in courting males. Males had considerably higher levels of OA circulating in their haemolymph than females and female OA level increased with female mass. Our experimental design cannot disentangle cause from effect, but our results are consistent with the hypothesis that OA plays a role in regulating mating tactic expression in R.punctulata. © 2014 . Source

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