Seasonal changes of hippocampus volume in parasitic cowbirds

Clayton, Nicola S.; Reboreda, Juan C.; Kacelnik, Alex

doi:10.1016/s0376-6357(97)00050-8

Cited by 94 publications

(108 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our results demonstrate sex-specific changes in the size of brain regions in birds and agree with the hypothesis that experience with nest searching is necessary for the seasonal increase of Hp volume seen in brood-parasitic female cowbirds (Clayton & Reboreda, 1997 Thus, it appears that housing cowbirds in large outdoor aviaries without host nests induces either a female-specific reduction in Hp volume compared to wild-caught cowbirds or a failure of the Hp to grow in captive birds compare to wild-caught birds. Although we cannot differentiate between these two possibilities with these data, we believe it is more likely that differences between WCF and CF are due to a lack of seasonal increase in Hp volume in CF rather than an induced decrease in Hp volume in CF.…”

Section: Discussionsupporting

confidence: 89%

“…Both male and female screaming cowbirds (M. rufoaxillaris) show a reduction in Hp volume in the nonbreeding season compared to the breeding season (Clayton & Reboreda, 1997), thus male Hp plasticity is possible in cowbirds. Obviously, more research is needed to isolate why we found sexspecific effects of captivity on Hp volume in M. a. obscurus despite a lack of sex-specific Hp size in wild birds of the population we studied.…”

Section: Cowbird Population Differencesmentioning

confidence: 99%

See 1 more Smart Citation

Sex differences in the effects of captivity on hippocampus size in brown-headed cowbirds (Molothrus ater obscurus).

Day

Guerra²,

Schlinger³

et al. 2008

Behavioral Neuroscience

View full text Add to dashboard Cite

In brood parasitic cowbirds, hippocampus (Hp) size is correlated with environmental spatial memory demands. Searching for host nests is the presumed causal factor influencing cowbird Hp size, because Hp volumes vary across species, sexes, and seasons according to nest-searching participation. Brownheaded cowbirds have female-only nest searching and, at least in the eastern subspecies, a larger Hp in females than in males, suggesting that nest searching influences cowbird Hp size. We predicted that female brown-headed cowbirds housed in aviaries lacking host nests would have a smaller Hp than wild-caught females whereas males would be unaffected. We found that the Hp was smaller in captive females, but not males, compared to their wild-caught counterparts. This did not appear to be due to general effects of an impoverished environment on all brain regions. Our results imply that interruption of nest searching in cowbirds prevents seasonal increase in Hp size in females. Future studies should isolate which behavioral differences between wild and captive birds contributed to captivity-induced changes in Hp volume in females while not affecting males. Keywordscowbird; hippocampus; sex differences; brain plasticity; brood parasitism Variation in environmental spatial demands is related to variation in hippocampus (Hp) size among closely related species, between sexes, and across seasons in mammalian, avian, and reptilian species. For example, food-storing behaviors in birds (Clayton, 1995a;Hampton, Sherry, Shettleworth, Kurgel, & Ivy, 1995;Hampton & Shettleworth, 1996;Healy & Krebs, 1992;Krebs, Sherry, Healy, Perry, & Vaccarion, 1989;Sherry, Vaccarino, Buckenham, & Herz, 1989;Volman, Grubb, & Schuett, 1997) and rodents (Jacobs, 1992;Jacobs & Spencer, 1994), foraging-related rate of movement in lacertid lizards (Day, Crews, & Wilczynski, 1999), home-range size in voles (Gaulin, 1992;Jacobs, Gaulin, Sherry, & Hoffman, 1990 Sherry, Jacobs, & Gaulin, 1992), and breeding-habitat complexity in petrels (Abbott, Walsh, Storey, Stenhause, & Harley, 1999) are all associated with enlarged Hp size, presumably due to the demands of spatial memory. In addition, seasonal variation in food-storing demands is associated with seasonal changes in Hp volume (Smulders, Sasson, & DeVoogd, 1995) in black-capped chickadees and rodents (Jacobs, 1996). Males have a larger Hp than females in a vole species in which males have larger home ranges but not in vole species that do not have sex differences in home range (Gaulin, 1992). These results provide evidence that environmental or experiential seasonal changes can alter Hp volume and that natural and sexual selection on a variety of spatial-related skills has produced a larger Hp in some species or sexes than in others.Although correlations of Hp volume with ecological demands for spatial ability are numerous, the specific mechanisms that contribute to such adult variation in the volume of the Hp are not well understood. We do know that species-specific reactions to spatial experience...

show abstract

Section: Discussionsupporting

confidence: 89%

Section: Cowbird Population Differencesmentioning

confidence: 99%

Sex differences in the effects of captivity on hippocampus size in brown-headed cowbirds (Molothrus ater obscurus).

Day

Guerra²,

Schlinger³

et al. 2008

Behavioral Neuroscience

View full text Add to dashboard Cite

show abstract

“…Female cowbirds, which spend their mornings in their egg-laying range either alone or followed by males, parasitize nests before sunrise when it is still dark and must, therefore, have an accurate memory of the locations of potential host nests [6,8]. Female brown-headed cowbirds have a larger hippocampus than males, whereas no sex difference exists in related species that are not brood parasites [9][10][11]. This difference in the hippocampus size between males and females may be present only in the breeding season [11].…”

Section: Introductionmentioning

confidence: 99%

“…Female brown-headed cowbirds have a larger hippocampus than males, whereas no sex difference exists in related species that are not brood parasites [9][10][11]. This difference in the hippocampus size between males and females may be present only in the breeding season [11]. Sex and seasonal differences in spatial cognition in cowbirds, however, are not well understood [12].…”

Section: Introductionmentioning

confidence: 99%

Female cowbirds have more accurate spatial memory than males

Guigueno

Snow

MacDougall‐Shackleton

et al. 2014

Biol. Lett.

View full text Add to dashboard Cite

Brown-headed cowbirds (Molothrus ater) are obligate brood parasites. Only females search for host nests and they find host nests one or more days before placing eggs in them. Past work has shown that females have a larger hippocampus than males, but sex differences in spatial cognition have not been extensively investigated. We tested cowbirds for sex and seasonal differences in spatial memory on a foraging task with an ecologically relevant retention interval. Birds were trained to find one rewarded location among 25 after 24 h. Females made significantly fewer errors than males and took more direct paths to the rewarded location than males. Females and males showed similar search times, indicating there was no sex difference in motivation. This sex difference in spatial cognition is the reverse of that observed in some polygynous mammals and is consistent with the hypothesis that spatial cognition is adaptively specialized in this brood-parasitic species.

show abstract

“…48 behaviours are made necessary due to environmental variations (Clayton & Krebs, 1994) such 49 as seasonality (Clayton et al, 1997), food availability (Healy & Krebs, 1992) and urbanisation 50 (Mettke-Hofmann, 2016). Cognitive factors can also speed up evolutionary and ecological 51 pattern changes during periods of rapid environmental change or extremes as a result of 52 cognition driving coping mechanisms (Roth et al, 2015).…”

mentioning

confidence: 99%

Development rate rather than social environment influences cognitive performance in Australian black field crickets, Teleogryllus commodus

Anderson

Kasumovic

2017

Preprint

View full text Add to dashboard Cite

Cognitive functioning is vital for enabling animals of all taxa to optimise their chances of survival and reproductive success. Learning and memory in particular are drivers of many evolutionary processes. The field of cognitive ecology explores how the environment can affect investment into cognitive capacity and learning ability. In this study, we examine how developmental plasticity can affect cognitive ability by exploring the role of early social environment on influencing problem solving ability and learning of female black field crickets, Teleogryllus commodus. We used two learning paradigms, an analog of the Morris water maze and a novel linear maze, to examine cognitive differences between individuals Cognitive functioning is vital for enabling animals of all taxa to optimise their chances of 12 survival and reproductive success. Learning and memory in particular are drivers of many 13 evolutionary processes. The field of cognitive ecology explores how the environment can affect 14 investment into cognitive capacity and learning ability. In this study, we examine how 15 developmental plasticity can affect cognitive ability by exploring the role of early social 16 environment on influencing problem solving ability and learning of female black field crickets, 17 Teleogryllus commodus. We used two learning paradigms, an analog of the Morris water maze 18 and a novel linear maze, to examine cognitive differences between individuals reared in two 19 acoustic treatments: silence or calling. Although there was no evidence of learning or memory, 20 individuals that took longer to mature solved the Morris water maze more quickly. This 21 suggests that increased investment into cognitive development is likely associated with 22 increased development time during immature stages. Inconsistent individual performance and 23 motivation during the novel linear maze task highlights the difficulties of designing ecologically 24 relevant learning tasks within a lab setting. The role of experimental design in understanding 25 cognitive ability and learning in more natural circumstances is discussed. 27PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.2728v1 | CC BY 4.0 Open Access |

show abstract

Seasonal changes of hippocampus volume in parasitic cowbirds

Cited by 94 publications

References 21 publications

Sex differences in the effects of captivity on hippocampus size in brown-headed cowbirds (Molothrus ater obscurus).

Sex differences in the effects of captivity on hippocampus size in brown-headed cowbirds (Molothrus ater obscurus).

Female cowbirds have more accurate spatial memory than males

Development rate rather than social environment influences cognitive performance in Australian black field crickets, Teleogryllus commodus

Contact Info

Product

Resources

About