Does Feeding Behavior Facilitate Trophic Niche Partitioning in Two Sympatric Sucker Species from the American Southwest?

Abstract

We examined two sympatric desert fishes, Sonora suckers (Catostomus insignis) and desert suckers (Pantosteus clarkii), and asked, does feeding behavior facilitate trophic niche partitioning? To answer this question, we conducted laboratory-based feeding trials to determine whether morphology alone facilitates the diet separation between the relatively unspecialized, omnivorous Sonora sucker and the more morphologically specialized, algivorous desert sucker or whether behavioral differences accompany morphological specialization. We predicted that (1) algivorous desert suckers would maximize contact between jaws and substrate and produce a large mouth-gape to facilitate scraping attached food-material; (2) omnivorous Sonora suckers would be more effective suction feeders when consuming unattached food items from the benthos; and (3) because they are anatomically specialized for scraping, desert suckers could not alter their feeding behavior when presented with different prey types, whereas relatively unspecialized Sonora suckers could vary behavior with prey type. We found that both species maximized jaw contact when feeding on benthic-attached food, although desert suckers produced a greater gape area. We also found that Sonora suckers were more effective suction feeders when feeding on benthic-unattached prey. Counter to our initial predictions, both species altered key aspects of feeding behavior in response to different prey types/locations. It appears that both sucker species can function as generalist feeders to exploit a variety of prey types within their natural habitat; indeed, this behavioral versatility may allow desert and Sonora suckers to respond to the cyclic environmental changes that are characteristic of the aquatic habitats of the American Southwest.

Rapid adaptive evolution of scale-eating kinematics to a novel ecological niche

“…This large gape and unique jaw alignment may allow scale-eaters to attack prey from a roughly perpendicular angle (as frequently observed during field observations), whereby they appear to wrap their large lower jaw under prey items and subsequently scraping scales from their sides using their independently protrusible upper jaws (also observed in a scale-eating characin: Hata et al, 2011). Interestingly, perpendicular angles of attack and large gapes are associated with scraping in benthic feeding fish (Van Wassenbergh et al, 2008;O'Neill and Gibb, 2013). In fact, two prominent hypotheses for the origins of scale-eating are that it arose from: (1) an algae-scraping ancestor or (2) an ancestor specializing on scraping parasites from other fish (Sazima, 1983).…”

Modulation of shark prey capture kinematics in response to sensory deprivation

“…Among bony fishes, modulation has generally been considered to occur in response to different prey types, locations, sizes, shapes, textures, and degrees of elusivity (Nyberg, 1971;Elshoud-Oldendave and Osse, 1976;Liem, 1978Liem, , 1979Liem, , 1980Lauder, 1981Lauder, , 1983Wainwright and Lauder, 1986;Wainwright, 1988;Norton, 1991aNorton, , 1995Norton and Brainerd, 1993;Frost and Sanford, 1999;Van Wassenbergh et al, 2006;O'Neill and Gibb, 2014). The behavior, and therefore motor pattern chosen, is believed to depend on information gathered prior to the initiation of the strike (Liem, 1979).…”

Changing environmental gradients over forty years alter ecomorphological variation in Guadalupe Bass Micropterus treculii throughout a river basin

“…Our results along with those of Kern and Langerhans (2018) suggest that anthropogenic alteration has the ability to alter fish morphology, and this continued environmental change could impact ecosystem structure and function (Bassar et al, 2010;Crutsinger, 2016). These results contribute to an understanding of trait variation that may help to buffer populations under conditions of increased urbanization and sprawl, human population growth, and climate risk, all of which impose novel selective pressure on species (Nelson et al, 2009;Reed, Waples, Schindler, Hard, & Kinnison, 2010), especially endemic species like Guadalupe Bass (Kwon et al, 2012;McDonald et al, 2011).…”