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Males of a strongly polygynous species consume more poisonous food than females.

Bravo C, Bautista LM, García-París M, Blanco G, Alonso JC - PLoS ONE (2014)

Bottom Line: The male-biased consumption suggests that males could use cantharidin to reduce their parasite load and increase their sexual attractiveness.A white, clean cloaca with no infection symptoms (e.g., diarrhoea) is an honest signal of both, resistance to cantharidin and absence of parasites, and represents a reliable indicator of the male quality to the extremely choosy females.Our results do not definitely prove, but certainly strongly suggest that cantharidin, obtained by consumption of blister beetles, acts in great bustards as an oral anti-microbial and pathogen-limiting compound, and that males ingest these poisonous insects to increase their mating success, pointing out that self-medication might have been overlooked as a sexually-selected mechanism enhancing male fitness.

View Article: PubMed Central - PubMed

Affiliation: Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Madrid, Spain.

ABSTRACT
We present evidence of a possible case of self-medication in a lekking bird, the great bustard Otis tarda. Great bustards consumed blister beetles (Meloidae), in spite of the fact that they contain cantharidin, a highly toxic compound that is lethal in moderate doses. In addition to anthelminthic properties, cantharidin was effective against gastrointestinal bacteria that cause sexually-transmitted diseases. Although both sexes consumed blister beetles during the mating season, only males selected them among all available insects, and ingested more and larger beetles than females. The male-biased consumption suggests that males could use cantharidin to reduce their parasite load and increase their sexual attractiveness. This plausibly explains the intense cloaca display males perform to approaching females, and the meticulous inspection females conduct of the male's cloaca, a behaviour only observed in this and another similar species of the bustard family. A white, clean cloaca with no infection symptoms (e.g., diarrhoea) is an honest signal of both, resistance to cantharidin and absence of parasites, and represents a reliable indicator of the male quality to the extremely choosy females. Our results do not definitely prove, but certainly strongly suggest that cantharidin, obtained by consumption of blister beetles, acts in great bustards as an oral anti-microbial and pathogen-limiting compound, and that males ingest these poisonous insects to increase their mating success, pointing out that self-medication might have been overlooked as a sexually-selected mechanism enhancing male fitness.

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Blister beetles Berberomeloe majalis (A) and Physomeloe corallifer (D) displaying their characteristic red and black aposematic warning coloration.Adults only appear in spring. Defensive reactions in B. majalis (B, C) involve thanatosis and autohaemorrhea, with large droplets of red haemolymph containing cantharidin expelled through thoracic and limb segment joints. Red tegumentary protuberances in the thorax of P. corallifer (E) permanently mimic haemolymph droplets. Photographs: M. García-París.
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pone-0111057-g001: Blister beetles Berberomeloe majalis (A) and Physomeloe corallifer (D) displaying their characteristic red and black aposematic warning coloration.Adults only appear in spring. Defensive reactions in B. majalis (B, C) involve thanatosis and autohaemorrhea, with large droplets of red haemolymph containing cantharidin expelled through thoracic and limb segment joints. Red tegumentary protuberances in the thorax of P. corallifer (E) permanently mimic haemolymph droplets. Photographs: M. García-París.

Mentions: In this context, we examine here the consumption of poisonous insects by great bustards (Otis tarda) during the mating season. The great bustard is a polygynous bird with one of the most strongly skewed male mating success values among birds [13]. Males gather each year at traditional arenas (leks) where they perform elaborate sexual exhibitions directed towards females in order to express their status and condition [14]. Great bustards are among the few birds that feed on blister beetles (Berberomeloe majalis, Physomeloe corallifer; Fig. 1) [15],[16]. These insects are avoided by most animals because they contain cantharidin, a bitter-tasting and highly toxic defensive chemical with high immunogenicity [17] that acts in blister beetles as fungicide and nematocide [18]. Only a few species, such as the spur-winged goose Plectropterus gambensis and the northern leopard frogs Rana pipiens consume blister beetles, with a likely side effect of becoming toxic to predators [19],[20]. Cantharidin is also a well-known aphrodisiac compound that was obtained in the past from a beetle known as Spanish fly [21]. In humans, it causes priapism in men and pelvic congestion in women [22],[23]. Cantharidin-tolerant foragers would benefit from its anti-microbial and anthelminthic properties [24], and thus could enhance their health and their attractiveness to potential mates during the mate selection process.


Males of a strongly polygynous species consume more poisonous food than females.

Bravo C, Bautista LM, García-París M, Blanco G, Alonso JC - PLoS ONE (2014)

Blister beetles Berberomeloe majalis (A) and Physomeloe corallifer (D) displaying their characteristic red and black aposematic warning coloration.Adults only appear in spring. Defensive reactions in B. majalis (B, C) involve thanatosis and autohaemorrhea, with large droplets of red haemolymph containing cantharidin expelled through thoracic and limb segment joints. Red tegumentary protuberances in the thorax of P. corallifer (E) permanently mimic haemolymph droplets. Photographs: M. García-París.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4206510&req=5

pone-0111057-g001: Blister beetles Berberomeloe majalis (A) and Physomeloe corallifer (D) displaying their characteristic red and black aposematic warning coloration.Adults only appear in spring. Defensive reactions in B. majalis (B, C) involve thanatosis and autohaemorrhea, with large droplets of red haemolymph containing cantharidin expelled through thoracic and limb segment joints. Red tegumentary protuberances in the thorax of P. corallifer (E) permanently mimic haemolymph droplets. Photographs: M. García-París.
Mentions: In this context, we examine here the consumption of poisonous insects by great bustards (Otis tarda) during the mating season. The great bustard is a polygynous bird with one of the most strongly skewed male mating success values among birds [13]. Males gather each year at traditional arenas (leks) where they perform elaborate sexual exhibitions directed towards females in order to express their status and condition [14]. Great bustards are among the few birds that feed on blister beetles (Berberomeloe majalis, Physomeloe corallifer; Fig. 1) [15],[16]. These insects are avoided by most animals because they contain cantharidin, a bitter-tasting and highly toxic defensive chemical with high immunogenicity [17] that acts in blister beetles as fungicide and nematocide [18]. Only a few species, such as the spur-winged goose Plectropterus gambensis and the northern leopard frogs Rana pipiens consume blister beetles, with a likely side effect of becoming toxic to predators [19],[20]. Cantharidin is also a well-known aphrodisiac compound that was obtained in the past from a beetle known as Spanish fly [21]. In humans, it causes priapism in men and pelvic congestion in women [22],[23]. Cantharidin-tolerant foragers would benefit from its anti-microbial and anthelminthic properties [24], and thus could enhance their health and their attractiveness to potential mates during the mate selection process.

Bottom Line: The male-biased consumption suggests that males could use cantharidin to reduce their parasite load and increase their sexual attractiveness.A white, clean cloaca with no infection symptoms (e.g., diarrhoea) is an honest signal of both, resistance to cantharidin and absence of parasites, and represents a reliable indicator of the male quality to the extremely choosy females.Our results do not definitely prove, but certainly strongly suggest that cantharidin, obtained by consumption of blister beetles, acts in great bustards as an oral anti-microbial and pathogen-limiting compound, and that males ingest these poisonous insects to increase their mating success, pointing out that self-medication might have been overlooked as a sexually-selected mechanism enhancing male fitness.

View Article: PubMed Central - PubMed

Affiliation: Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Madrid, Spain.

ABSTRACT
We present evidence of a possible case of self-medication in a lekking bird, the great bustard Otis tarda. Great bustards consumed blister beetles (Meloidae), in spite of the fact that they contain cantharidin, a highly toxic compound that is lethal in moderate doses. In addition to anthelminthic properties, cantharidin was effective against gastrointestinal bacteria that cause sexually-transmitted diseases. Although both sexes consumed blister beetles during the mating season, only males selected them among all available insects, and ingested more and larger beetles than females. The male-biased consumption suggests that males could use cantharidin to reduce their parasite load and increase their sexual attractiveness. This plausibly explains the intense cloaca display males perform to approaching females, and the meticulous inspection females conduct of the male's cloaca, a behaviour only observed in this and another similar species of the bustard family. A white, clean cloaca with no infection symptoms (e.g., diarrhoea) is an honest signal of both, resistance to cantharidin and absence of parasites, and represents a reliable indicator of the male quality to the extremely choosy females. Our results do not definitely prove, but certainly strongly suggest that cantharidin, obtained by consumption of blister beetles, acts in great bustards as an oral anti-microbial and pathogen-limiting compound, and that males ingest these poisonous insects to increase their mating success, pointing out that self-medication might have been overlooked as a sexually-selected mechanism enhancing male fitness.

Show MeSH
Related in: MedlinePlus