Quantity discrimination in parental fish: female convict cichlid discriminate fry shoals of different sizes

Abstract

Numerical abilities have been found to be adaptive in different contexts, including mating, foraging, fighting assessment and antipredator strategies. In species with parental care, another potential advantage is the possibility to adjust parental behavior in relation to the numerosity of the progeny. The finding that many fish vary their parental investment in relation to brood size advocates the existence of a mechanism for appraising offspring number, an aspect that has never been directly investigated. Here we tested the ability of parental female convict cichlid (Amatitlania nigrofasciata) to discriminate between two fry groups differing in number by measuring time spent attempting to recover groups of fry experimentally displaced from the next. Females spent more time trying to recover the fry from larger groups when tested with contrasts 6 versus 12 (1:2) and 6 versus 9 fry (2:3); however, they showed no preference in the 6 versus 8 (3:4) contrast, suggesting that this task exceeds their discrimination capacity.

Understanding the origin of number sense: a review of fish studies

“…As we saw before, a variety of different methods have been apparently used with fish. Regarding the spontaneous preference paradigm, fish have been tested for their ability to discriminate among different numbers of companions, in foraging contexts for their preference for quantities of food items, in parental contexts while retrieving different quantities of fry and in assessments of the numbers of potential mates and rivals [6,10,13,16]. Also, extremely heterogeneous training procedures have been used with fish [30].…”

“…Also, the risk of an individual fish being caught statistically diminishes as the quantity of individuals in the group increases (the dilution effect, see [15]). The ability to discriminate the larger shoal probably provides advantages in parental care, as convict cichlid parents allocate more effort to larger groups when retrieving fry that have fled from the nest [16]. Some other ecological functions of numerical abilities are very specific and are expected to be present in only a few species.…”

Quantity discrimination in angelfish (Pterophyllum scalare) is maintained after a 30-s retention interval in the large but not in the small number range

“…A diversity of nonhuman animals, as well as humans, possess nonverbal ability to discriminate between different quantities of items (reviewed in Feigenson et al 2004). This ability has evolutionary advantages since it allows individuals to distinguish places with more food (Lucon-Xiccato et al 2015), the size of the rival groups (Benson-Amram et al 2011), the number of mates (Lemaître et al 2011), the number of shoaling members for protection (Agrillo et al 2007), the brood size for parental investment (Forsaktar et al 2016), the more vulnerable group of prey for hunting (Panteleeva et al 2013) or the larger social group more ideal for protection in potentially dangerous environments (Hager and Helfman 1991). Given such advantages, it is not surprising that the ability to discriminate between sets of items differing in number has been found in a wide range of animal species (reviewed in Reznikova and Ryabko 2011).…”

Plasticity in activity and latency to explore differs between juvenile Atlantic cod Gadus morhua across a temperature gradient

“…Nevertheless, the individuals differed in their response to increased temperature (Table ). This result adds to an accumulating number of studies that show that fluctuations in temperature can have effects on measures of animal behavioural consistency (Biro et al ., ; Briffa et al ., ; Forsatkar et al ., ; Colchen et al ., ). Visual inspection of the fitted individual slopes across temperature (Fig.…”