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Evidence for aggressive mimicry in an adult brood parasitic bird, and generalized defences in its host.

Feeney WE, Troscianko J, Langmore NE, Spottiswoode CN - Proc. Biol. Sci. (2015)

Bottom Line: Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings.However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk.We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest.

View Article: PubMed Central - PubMed

Affiliation: Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia Department of Zoology, University of Cambridge, Cambridge, UK william.e.feeney@gmail.com.

ABSTRACT
Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings. However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk. We tested the hypothesis that female cuckoo finches (Anomalospiza imberbis) are aggressive mimics of female Euplectes weavers, such as the harmless, abundant and sympatric southern red bishop (Euplectes orix). We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest. This is, to our knowledge, the first quantitative evidence for aggressive mimicry in an adult bird, and suggests that host-parasite coevolution can select for aggressive mimicry by avian brood parasites, and counter-defences by hosts, at all stages of the reproductive cycle.

No MeSH data available.


Related in: MedlinePlus

(a) Mean number of alarm calls made to each model type: female cuckoo finch, male cuckoo finch, female southern red bishop and male southern red bishop. (b) Time spent mobbing (within 50 cm) each model by at least one prinia during the 300 s trial. (c) Mean colour difference (measured in JNDs) of accepted and rejected experimental eggs following presentation of a female cuckoo finch, female bishop or male bishop. p-values for pairwise comparisons were obtained by varying the reference category in the models. Asterisks denote significant differences and whiskers show ranges.
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RSPB20150795F3: (a) Mean number of alarm calls made to each model type: female cuckoo finch, male cuckoo finch, female southern red bishop and male southern red bishop. (b) Time spent mobbing (within 50 cm) each model by at least one prinia during the 300 s trial. (c) Mean colour difference (measured in JNDs) of accepted and rejected experimental eggs following presentation of a female cuckoo finch, female bishop or male bishop. p-values for pairwise comparisons were obtained by varying the reference category in the models. Asterisks denote significant differences and whiskers show ranges.

Mentions: In accordance with the visual modelling results, prinias did not distinguish between an adult female cuckoo finch and female bishop near their nest. There was no difference in the number of alarm calls they made towards a female cuckoo finch compared with a female bishop (p = 0.80; figure 3a), and nor was there a difference in the amount of time prinias spent mobbing the two models (p = 0.99; figure 3b). However, prinias were more aggressive towards the females of both species than they were to a male cuckoo finch and a male bishop: prinias spent significantly more time mobbing, and made more alarm calls towards a female cuckoo finch than either a male cuckoo finch (p = 0.0008; p = 0.0017, respectively) or a male bishop (p < 0.0001; p = 0.0003, respectively) (figure 3a,b). Although not quantified, in the majority of trials we also observed prinias physically attacking the female cuckoo finch and female bishop models; this degree of physical aggression was never observed during either of the male model trials. Taken together, these results suggest that hosts have evolved generalized counter-defences against potentially parasitic intruders.FigureĀ 3.


Evidence for aggressive mimicry in an adult brood parasitic bird, and generalized defences in its host.

Feeney WE, Troscianko J, Langmore NE, Spottiswoode CN - Proc. Biol. Sci. (2015)

(a) Mean number of alarm calls made to each model type: female cuckoo finch, male cuckoo finch, female southern red bishop and male southern red bishop. (b) Time spent mobbing (within 50 cm) each model by at least one prinia during the 300 s trial. (c) Mean colour difference (measured in JNDs) of accepted and rejected experimental eggs following presentation of a female cuckoo finch, female bishop or male bishop. p-values for pairwise comparisons were obtained by varying the reference category in the models. Asterisks denote significant differences and whiskers show ranges.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590487&req=5

RSPB20150795F3: (a) Mean number of alarm calls made to each model type: female cuckoo finch, male cuckoo finch, female southern red bishop and male southern red bishop. (b) Time spent mobbing (within 50 cm) each model by at least one prinia during the 300 s trial. (c) Mean colour difference (measured in JNDs) of accepted and rejected experimental eggs following presentation of a female cuckoo finch, female bishop or male bishop. p-values for pairwise comparisons were obtained by varying the reference category in the models. Asterisks denote significant differences and whiskers show ranges.
Mentions: In accordance with the visual modelling results, prinias did not distinguish between an adult female cuckoo finch and female bishop near their nest. There was no difference in the number of alarm calls they made towards a female cuckoo finch compared with a female bishop (p = 0.80; figure 3a), and nor was there a difference in the amount of time prinias spent mobbing the two models (p = 0.99; figure 3b). However, prinias were more aggressive towards the females of both species than they were to a male cuckoo finch and a male bishop: prinias spent significantly more time mobbing, and made more alarm calls towards a female cuckoo finch than either a male cuckoo finch (p = 0.0008; p = 0.0017, respectively) or a male bishop (p < 0.0001; p = 0.0003, respectively) (figure 3a,b). Although not quantified, in the majority of trials we also observed prinias physically attacking the female cuckoo finch and female bishop models; this degree of physical aggression was never observed during either of the male model trials. Taken together, these results suggest that hosts have evolved generalized counter-defences against potentially parasitic intruders.FigureĀ 3.

Bottom Line: Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings.However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk.We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest.

View Article: PubMed Central - PubMed

Affiliation: Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia Department of Zoology, University of Cambridge, Cambridge, UK william.e.feeney@gmail.com.

ABSTRACT
Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings. However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk. We tested the hypothesis that female cuckoo finches (Anomalospiza imberbis) are aggressive mimics of female Euplectes weavers, such as the harmless, abundant and sympatric southern red bishop (Euplectes orix). We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest. This is, to our knowledge, the first quantitative evidence for aggressive mimicry in an adult bird, and suggests that host-parasite coevolution can select for aggressive mimicry by avian brood parasites, and counter-defences by hosts, at all stages of the reproductive cycle.

No MeSH data available.


Related in: MedlinePlus