Single target acuity in the common sunfish (Lepomis gibbosus)

Abstract

Vision is considered to contribute to foraging, territorial, and reproductive behavior in sunfish. In these contexts, sunfish need to perceive single targets, such as prey items or body markings from either conspecifics or individuals of other sunfish species, from some distances. We determined the single target acuity of six common sunfish in a behavioral experiment to assess whether the visual abilities of sunfish correspond with behavioral observations or reactive distance measures and thus to assess the limits of vision regarding the mentioned behaviors. Single target acuity for full-contrast single targets amounted to 0.17 (0.13 - 0.32) deg. When contrast was reduced to Weber contrasts of 0.67 and 0.41, single target acuity dropped to 0.34 (0.31 - 0.37) deg, and finally to 0.42 (0.34 - 0.54) deg. Single target acuity would thus allow common sunfish to perceive biologically relevant stimuli at reasonable distances even when contrast is reduced.

The importance of visual and chemical cues in infection detection and avoidance in a freshwater fish

“…Pumpkinseed sunfish are a gregarious species that use sight to engage in behaviours such as mating, predation and agonistic interactions (Blanckenhorn, 1992; Kieffer & Colgan, 1991; Miller, 1963; Spratte et al, 2021; Stacey & Chiszar, 1978; Vila-Gispert & Moreno-Amich, 2004). Based on these characteristics, we first established individual social preference in a binary choice experiment as a proof of concept to evaluate pumpkinseeds’ use of visual cues in choosing shoal mates.…”

“…Many studies show that pumpkinseeds use visual cues for social behaviours such as recognition, mating and agonistic interactions (Kieffer & Colgan, 1991; Miller, 1963; Spratte et al, 2021; Stacey & Chiszar, 1978). Studies carried out in the context of chemical cues tend to focus on predator avoidance and local risk assessment using conspecific and heterospecific alarm substances (Leduc et al, 2003; Marcus & Brown, 2003; Xia et al, 2018).…”

“…Considering that both types of communication are essential for social behaviours, pumpkinseeds may be impacted by the modification of sensory landscapes due to global changes. Indeed, the detection of chemical cues in pumpkinseeds can be altered by water acidity (Leduc et al, 2003) and their visual acuity is influenced by the physical characteristics of the environment (Spratte et al, 2021). By altering the chemical and visual landscapes of waterbodies, the threats posed by acid rain, browning and eutrophication of freshwater ecosystems is a growing concern to researchers interested in sensory ecology, and the implications of such changes to disease ecology warrants further investigation (Dominoni et al, 2020; Mucci et al, 2011; Rivest et al, 2019; Schindler, 1988; Vander Zanden & Vadeboncoeur, 2020).…”

“…Considering that experienced fish showed the same response as naive ones, we suggest that pumpkinseeds do not use visual cues to discriminate between shoal mates infected with black spot disease. Previous work has shown that pumpkinseeds use a variety of visual cues and can identify conspecifics and related species up to a few meters away (Kieffer & Colgan, 1991; Miller, 1963; Spratte et al, 2021; Stacey & Chiszar, 1978). Consequently, they likely have the ability to see blackspots (i.e.…”

“…Both parasites are known to have considerable physiological and behavioural impacts on their hosts (Gradito, 2023; Harrison & Hadley, 1982; Lemly & Esch, 1984; Thelamon, 2023; Tobler & Schlupp, 2007). Sunfish rely on both visual and chemical cues to initiate a range of behavioural responses (Leduc et al, 2003; Marcus & Brown, 2003; Miller, 1963; Stacey & Chiszar, 1978) and have single target acuity (Spratte et al, 2021). Thus, pumpkinseeds may have the ability to perceive and respond to visual and/or chemical cues of infection.…”