The Mexican tetra Astyanax fasciatus has evolved a variety of more or less color- and eyeless cave populations. Here we examined the evolution of the female preference for large male body size within different populations of this species, either surface- or cave-dwelling. Given the choice between visual cues from a large and a small male, females from the surface form as well as females from an eyed cave form showed a strong preference for large males. When only non-visual cues were presented in darkness, the surface females did not prefer either males. Among the six cave populations studied, females of the eyed cave form and females of one of the five eyeless cave populations showed a preference for large males. Apparently, not all cave populations of Astyanax have evolved non-visual mating preferences. We discuss the role of selection by benefits of non-visual mate choice for the evolution of non-visual mating preferences.

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Female mating preferences in blind cave tetras Astyanax fasciatus (Characidae, Teleostei)

Nicotinamide phosphoribosyltransferase (NAMPT) is a pleiotropic protein that functions as an enzyme, cytokine, growth factor and hormone. As a target for oncology, NAMPT is particularly attractive, because it catalyzes the rate-limiting step in the salvage pathway to generate nicotinamide adenine dinucleotide (NAD), a universal energy- and signal-carrying molecule involved in cellular energy metabolism and many homeostatic functions. Inhibition of NAMPT generally results in NAD depletion, followed by ATP reduction and loss of cell viability. Herein, we describe NAMPT inhibitor (NAMPTi)-induced cardiac toxicity in rodents following short-term administration (2-7 days) of NAMPTi's. The cardiac toxicity was interpreted as a functional effect leading to congestive heart failure, characterized by sudden death, thoracic and abdominal effusion, and myocardial degeneration. Based on exposures in the initial in vivo safety rodent studies and cardiotoxicity observed, we conducted studies in rat and human in vitro cardiomyocyte cell systems. Based on those results, combined with human cell line potency data, we demonstrated the toxicity is both on-target and likely human relevant. This toxicity was mitigated in vitro by co-administration of nicotinic acid (NA), which can enable NAD production through the NAMPT-independent pathway; however, this resulted in only partial mitigation in in vivo studies. This work also highlights the usefulness and predictivity of in vitro cardiomyocyte assays using human cells to rank-order compounds against potency in cell-based pharmacology assays. Lastly, this work strengthens the correlation between cardiomyocyte cell viability and functionality, suggesting that these assays together may enable early assessment of cardiotoxicity in vitro prior to conduct of in vivo studies and potentially reduce subsequent attrition due to cardiotoxicity.

Cardiotoxicity Associated with Nicotinamide Phosphoribosyltransferase Inhibitors in Rodents and in Rat and Human-Derived Cells Lines.

Sexual selection is a possible mechanism of speciation. This could be true even in systems where female mate choice has not been clearly observed, because pre-existing biases may be expressed if female decision-making results in male trait evolution. In some mollies, males have enlarged dorsal fins and courtship display is the prevailing mating process. In others, male dominance is thought to play a greater role. We tested females of a species in the latter group, Poecilia mexicana, for consistent preference related to dorsal fin morphology. We found that females were biased toward larger dorsal fins. This latent preference could be an important driver in trait evolution.

Female choice linked to male dorsal fin height in a shortfin molly

We investigated the associative behavior of the female molly (Pisces: Poeciliidae), Poecilia gilli (Kner), collected from two Panamanian populations—one from a clear running forest stream and the other from an impacted suburban stream. We tested the hypotheses that females would preferentially associate with males and females of their local population versus the foreign population and that males would prefer local females. We also tested the hypothesis that morphological distinctions between the two populations can be made. We found that females preferentially associated with local males but preferred neither local nor foreign females. Males exhibited no preference for females based on stream of origin. Dorsal fin height differed between populations but sex had no effect on this trait. Ecological factors or female preference could be responsible for this divergence, which could be reinforced by female preference for local males.

Female Associative Behavior Accompanies Morphological Distinction in Two Panamanian Populations of the Molly Poecilia gilli (Kner)

In many species females choose a mate from among several available males; in other species, the social system provides no apparent opportunity for making a decision among alternative suitors, and decision-making capacity is assumed to be minimal. The origins, bases, and logic of female mate choices are contentious questions with important cognitive implications. Female short-finned mollies, Poecilia sphenops, have never been observed to choose mates in the wild, where instead a male-contest social system prevails. Nevertheless they readily choose between models of males in the laboratory. Some of their decisions anticipate features found in males in more recently evolved species where the social system permits female choice. The willingness of females to choose traits in a species without such traits or evident need or opportunity for female choice in the wild is remarkable. These observations suggest that choice behavior can be latent in a species, and may direct or bias the development of behavioral preferences.

Tanja S. Zabka

Papers

Possible decision-making preadaptations in the molly Poecilia sphenops