Introduction

Method

DIFFERENTIAL REARING CONDITIONS AFFECT EMOTIONAL REACTIVITY IN BOBWHITE QUAIL (Colinus virginianus) 

Eric J. Martinez, Joshua Herrington, and Robert LickliterFlorida International University, Miami, Florida

Conclusions

Tonic Immobility Task

Emergence Task

This research was supported by NSF grant BCS 1057898

Travel funds provided by the NIH (NICHD) and the Sackler Institute

Tonic Immobility On average, birds that were reared in opaque tubs (M = 212.32, SE = 17.74) experienced heightened levels of emotional reactivity compared to birds reared in clear tubs (M = 133.35, SE = 17.52). Non-parametric Mann-Whitney-U tests suggested significant differences in the duration of tonic immobility between the clear and opaque groups, with a Mann-Whitney score of U = 345.00, z = -2.901, p < .001, and a medium effect size (r = -.35).

Table 1: Average Time Spent in TI (s)

Groups Mean SD N=Clear 133.35 103.46 34Opaque 212.32 102.21 34

Emergence On average, birds that were reared in opaque tubs (M = 216.60, SE = 19.59) experienced heightened levels of emotional reactivity compared to birds reared in clear tubs (M = 139.97, SE = 20.69). Mann-Whitney-U tests suggested significant differences in the duration of time spent in the emergence box between the clear and opaque groups, with a Mann-Whitney score of U = 617.50, a standard test statistic of z = 2.549, with p < .05, and a medium effect size (r = .33).

Table 2: Average Duration Before Emergence (s)

Groups Mean SD N=Clear 139.97 113.34 30Opaque 216.60 107.33 30

Figure 1: Tonic Immobility Task Apparatus

Figure 2: Emergence Task Apparatus

Tests of Emotional Reactivity Results

A large body of research has explored the effects of environmental enrichment on neural, physiological, and behavioral outcomes. Most of this work has compared physically or socially enriched rearing with standard laboratory rearing, resulting in large differences in experience between rearing conditions. More subtle differences in rearing conditions have rarely been explored. In the current study, we explored the effects rearing conditions that allowed increased opportunities for visual experience on emotional reactivity in bobwhite quail neonates. Previously, our lab reared bobwhite quail neonates in opaque plastic tubs following hatching, which limited the amount of visual experience available. Following a switch to clear plastic rearing tubs, there were anecdotal observations of bobwhite chicks displaying decreased fear responses during testing. This observation led us to conduct a systematic analysis of chicks’ emotional reactivity following several days of rearing in clear vs. opaque rearing tubs.

Immediately after hatching, quail neonates were transferred into one of two types of rearing tubs: a clear walled tub (C) or an opaque walled tub (O). Chicks in both conditions were socially reared in groups of 12-15 chicks and given feed and water ad libitum. Chicks remained in the same tub until time of testing, at approximately 72 hrs following hatch. All chicks were tested using one of two common measures of emotional reactivity in birds: a tonic immobility task (TI) or a hole-in-the-wall emergence task (ET). In the TI condition, we assessed the number of induction attempts needed to induce a tonic state. Latency of time spent immobile was also recorded. For the ET condition, chicks were scored on their latency to emerge from a covered box into a novel open field environment.

Chicks raised in clear rearing tubs showed significantly less emotional reactivity at 72 hr following hatching when compared to chicks reared in opaque rearing tubs. Our study has taken a first step to demonstrate that subtle aspects of early rearing environments can alter behavior in a precocial avian species. At this point, the mechanism(s) by which emotional reactivity was elevated in Opaque reared chicks is unknown; future studies will manipulate the amount and range of visual experience available in the days following hatching and assess emotional reactivity, as well as learning and memory.

Clear Rearing Tub Opaque Rearing Tub