Developmental effects of visual environment on species‐assortative mating preferences in Lake Victoria cichlid fish

Abstract

Local adaptation can be a potent force in speciation, with environmental heterogeneity leading to niche specialization and population divergence. However, local adaption often requires nonrandom mating to generate reproductive isolation. Population divergence in sensory properties can be particularly consequential in speciation, affecting both ecological adaptation and sexual communication. Pundamilia pundamila and Pundamilia nyererei are two closely related African cichlid species that differ in male coloration, blue vs. red. They co-occur at rocky islands in southern Lake Victoria, but inhabit different depth ranges with different light environments. The species differ in colour vision properties, and females exert species-specific preferences for blue vs. red males. Here, we investigated the mechanistic link between colour vision and preference, which could provide a rapid route to reproductive isolation. We tested the behavioural components of this link by experimentally manipulating colour perception - we raised both species and their hybrids under light conditions mimicking shallow and deep habitats - and tested female preference for blue and red males under both conditions. We found that rearing light significantly affected female preference: shallow-reared females responded more strongly to P. pundamilia males and deep-reared females favoured P. nyererei males - implying that visual development causally affects mate choice. These results are consistent with sensory drive predictions, suggesting that the visual environment is key to behavioural isolation of these species. However, the observed plasticity could also make the species barrier vulnerable to environmental change: species-assortative preferences were weaker in females that were reared in the other species' light condition.

Testing sensory drive speciation in cichlid fish: Linking light conditions to opsin expression, opsin genotype and female mate preference

“…We sequenced the LWS gene of females previously assessed for mate preference (Wright et al, 2017). Pundamilia from Python…”

“…A subset of females (n = 25) tested for mate preference (Wright et al, 2017) allowed us to explore the link between light-induced variation in opsin expression and variation in female preference be- The repeatability of individual preference behaviour in our prior study was low (R LD = 0.103; R Q = 0.07; females were tested multiple times; see Figure S4); thus, subtle relationships between female preference and opsin expression may have been masked by within-female variation. Therefore, we also calculated mean preference scores for each female and repeated the analyses.…”

“…Of the 91 females tested for preference behaviour (Wright et al, 2017), we were able to assign LWS genotype to 77 ( Figure 5). All blue females (both parents blue) were homozygous "PP" (n = 20).…”

Peer Review #1 of "Developmental effects of environmental light on male nuptial coloration in Lake Victoria cichlid fish (v0.1)"

“…Fish rearing & maintenance -Offspring of wild caught P. pundamilia and P. nyererei, collected at Python Islands in the Mwanza Gulf of Lake Victoria (-2.6237, 32.8567 in 2010 & 2014), were reared in light conditions mimicking those in shallow and deep waters at Python Islands (as in: Maan et al, 2017;Wright et al, 2017). Lab-bred lines (hybrid and non-hybrid) were created opportunistically as reciprocal crosses, with 18 dams and 14 sires.…”

Colour‐based foraging diverges after multiple generations under different light environments

“…Changes in environmental parameters that influence sensory systems will have consequences for sensory driven traits and behaviours (Endler & Basolo, 1998;McNaught & Owens, 2002;Seehausen et al, 2008). Environmentally driven changes in sensory processing are an important process in shaping the divergence and evolution of behaviours through environmentally induced changes in sensory parameters (Seehausen et al, 2008;Tobias et al, 2010;Wright et al, 2016). One such behaviour that is likely to be affected by changes in the sensory environment is visually based foraging behaviour (Endler 1992 Figure 1).…”