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Tropical parabiotic ants: Highly unusual cuticular substances and low interspecific discrimination.

Menzel F, Blüthgen N, Schmitt T - Front. Zool. (2008)

Bottom Line: It only tolerated workers of the Ca. rufifemur variety it was associated with, but attacked the respective others.However, Cr. modiglianii did not distinguish its own Ca. rufifemur partner from allocolonial Ca. rufifemur workers of the same variety.We conclude that there is a mutual substance transfer between Cr. modiglianii and Ca. rufifemur.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Freiburg, Institute of Biology I (Zoology), Department of Evolutionary Biology and Animal Ecology, Hauptstr,1, 79104 Freiburg, Germany. thomas.schmitt@biologie.uni-freiburg.de.

ABSTRACT

Background: Associations between animal species require that at least one of the species recognizes its partner. Parabioses are associations of two ant species which co-inhabit the same nest. Ants usually possess an elaborate nestmate recognition system, which is based on cuticular hydrocarbons and allows them to distinguish nestmates from non-nestmates through quantitative or qualitative differences in the hydrocarbon composition. Hence, living in a parabiotic association probably necessitates changes of the nestmate recognition system in both species, since heterospecific ants have to be accepted as nestmates.

Results: In the present study we report highly unusual cuticular profiles in the parabiotic species Crematogaster modiglianii and Camponotus rufifemur from the tropical rainforest of Borneo. The cuticle of both species is covered by a set of steroids, which are highly unusual surface compounds. They also occur in the Dufour gland of Crematogaster modiglianii in high quantities. The composition of these steroids differed between colonies but was highly similar among the two species of a parabiotic nest. In contrast, hydrocarbon composition of Cr. modiglianii and Ca. rufifemur differed strongly and only overlapped in three regularly occurring and three trace compounds. The hydrocarbon profile of Camponotus rufifemur consisted almost exclusively of methyl-branched alkenes of unusually high chain lengths (up to C49). This species occurred in two sympatric, chemically distinct varieties with almost no hydrocarbons in common. Cr. modiglianii discriminated between these two varieties. It only tolerated workers of the Ca. rufifemur variety it was associated with, but attacked the respective others. However, Cr. modiglianii did not distinguish its own Ca. rufifemur partner from allocolonial Ca. rufifemur workers of the same variety.

Conclusion: We conclude that there is a mutual substance transfer between Cr. modiglianii and Ca. rufifemur. Ca. rufifemur actively or passively acquires cuticular steroids from its Cr. modiglianii partner, while the latter acquires at least two cuticular hydrocarbons from Ca. rufifemur. The cuticular substances of both species are highly unusual regarding both substance classes and chain lengths, which may cause the apparent inability of Cr. modiglianii to discriminate Ca. rufifemur nestmates from allocolonial Ca. rufifemur workers of the same chemical variety.

No MeSH data available.


Related in: MedlinePlus

Relative abundance of 27-MeC39-14-ene and 27-MeC39-16-ene in Cr. modiglianii workers living with the red vs. Cr. modiglianii workers living with the black Ca. rufifemur variety. Median, quartiles, range, and outliers (i.e. all data points deviating from the box by more than 1.5 times the interquartile range) are shown in the present and the following figures. The number of analyzed colonies is given above each plot. ** highly significant (p = 0.0043) according to U test.
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Figure 2: Relative abundance of 27-MeC39-14-ene and 27-MeC39-16-ene in Cr. modiglianii workers living with the red vs. Cr. modiglianii workers living with the black Ca. rufifemur variety. Median, quartiles, range, and outliers (i.e. all data points deviating from the box by more than 1.5 times the interquartile range) are shown in the present and the following figures. The number of analyzed colonies is given above each plot. ** highly significant (p = 0.0043) according to U test.

Mentions: Six hydrocarbons were shared between both parabiotic species. The red Ca. rufifemur variety shared three hydrocarbons with Cr. modiglianii. These were the two methyl-branched alkenes, 27-MeC39-14-ene and 27-MeC39-16-ene, which are the main constituents of the red Ca. rufifemur surface profile, and its saturated derivative, 13-MeC39 (Table 1). All three are absent in the black Ca. rufifemur variety. Cr. modiglianii colonies living with the red Ca. rufifemur variety (henceforth, 'red' Cr. modiglianii) exhibited significantly more 27-MeC39-14-ene and 27-MeC39-16-ene than those associated with the black variety (henceforth, 'black' Cr. modiglianii) (Mann-Whitney W = 30, p = 0.0043; N1 = 5, N2 = 6 colonies, Figure 2). The quantities of 13-MeC39 were not compared since they could not be separated from other methyl-branched C39 alkanes in Cr. modiglianii (Table 1). Traces of three other hydrocarbons common in Cr. modiglianii were detected in the black Ca. rufifemur variety (C35:1, C35, C37-9-ene, Table 1). Albeit the associated Cr. modiglianii possessed slightly more C37-9-ene than those living with the red variety, no significant differences were found.


Tropical parabiotic ants: Highly unusual cuticular substances and low interspecific discrimination.

Menzel F, Blüthgen N, Schmitt T - Front. Zool. (2008)

Relative abundance of 27-MeC39-14-ene and 27-MeC39-16-ene in Cr. modiglianii workers living with the red vs. Cr. modiglianii workers living with the black Ca. rufifemur variety. Median, quartiles, range, and outliers (i.e. all data points deviating from the box by more than 1.5 times the interquartile range) are shown in the present and the following figures. The number of analyzed colonies is given above each plot. ** highly significant (p = 0.0043) according to U test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2577638&req=5

Figure 2: Relative abundance of 27-MeC39-14-ene and 27-MeC39-16-ene in Cr. modiglianii workers living with the red vs. Cr. modiglianii workers living with the black Ca. rufifemur variety. Median, quartiles, range, and outliers (i.e. all data points deviating from the box by more than 1.5 times the interquartile range) are shown in the present and the following figures. The number of analyzed colonies is given above each plot. ** highly significant (p = 0.0043) according to U test.
Mentions: Six hydrocarbons were shared between both parabiotic species. The red Ca. rufifemur variety shared three hydrocarbons with Cr. modiglianii. These were the two methyl-branched alkenes, 27-MeC39-14-ene and 27-MeC39-16-ene, which are the main constituents of the red Ca. rufifemur surface profile, and its saturated derivative, 13-MeC39 (Table 1). All three are absent in the black Ca. rufifemur variety. Cr. modiglianii colonies living with the red Ca. rufifemur variety (henceforth, 'red' Cr. modiglianii) exhibited significantly more 27-MeC39-14-ene and 27-MeC39-16-ene than those associated with the black variety (henceforth, 'black' Cr. modiglianii) (Mann-Whitney W = 30, p = 0.0043; N1 = 5, N2 = 6 colonies, Figure 2). The quantities of 13-MeC39 were not compared since they could not be separated from other methyl-branched C39 alkanes in Cr. modiglianii (Table 1). Traces of three other hydrocarbons common in Cr. modiglianii were detected in the black Ca. rufifemur variety (C35:1, C35, C37-9-ene, Table 1). Albeit the associated Cr. modiglianii possessed slightly more C37-9-ene than those living with the red variety, no significant differences were found.

Bottom Line: It only tolerated workers of the Ca. rufifemur variety it was associated with, but attacked the respective others.However, Cr. modiglianii did not distinguish its own Ca. rufifemur partner from allocolonial Ca. rufifemur workers of the same variety.We conclude that there is a mutual substance transfer between Cr. modiglianii and Ca. rufifemur.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Freiburg, Institute of Biology I (Zoology), Department of Evolutionary Biology and Animal Ecology, Hauptstr,1, 79104 Freiburg, Germany. thomas.schmitt@biologie.uni-freiburg.de.

ABSTRACT

Background: Associations between animal species require that at least one of the species recognizes its partner. Parabioses are associations of two ant species which co-inhabit the same nest. Ants usually possess an elaborate nestmate recognition system, which is based on cuticular hydrocarbons and allows them to distinguish nestmates from non-nestmates through quantitative or qualitative differences in the hydrocarbon composition. Hence, living in a parabiotic association probably necessitates changes of the nestmate recognition system in both species, since heterospecific ants have to be accepted as nestmates.

Results: In the present study we report highly unusual cuticular profiles in the parabiotic species Crematogaster modiglianii and Camponotus rufifemur from the tropical rainforest of Borneo. The cuticle of both species is covered by a set of steroids, which are highly unusual surface compounds. They also occur in the Dufour gland of Crematogaster modiglianii in high quantities. The composition of these steroids differed between colonies but was highly similar among the two species of a parabiotic nest. In contrast, hydrocarbon composition of Cr. modiglianii and Ca. rufifemur differed strongly and only overlapped in three regularly occurring and three trace compounds. The hydrocarbon profile of Camponotus rufifemur consisted almost exclusively of methyl-branched alkenes of unusually high chain lengths (up to C49). This species occurred in two sympatric, chemically distinct varieties with almost no hydrocarbons in common. Cr. modiglianii discriminated between these two varieties. It only tolerated workers of the Ca. rufifemur variety it was associated with, but attacked the respective others. However, Cr. modiglianii did not distinguish its own Ca. rufifemur partner from allocolonial Ca. rufifemur workers of the same variety.

Conclusion: We conclude that there is a mutual substance transfer between Cr. modiglianii and Ca. rufifemur. Ca. rufifemur actively or passively acquires cuticular steroids from its Cr. modiglianii partner, while the latter acquires at least two cuticular hydrocarbons from Ca. rufifemur. The cuticular substances of both species are highly unusual regarding both substance classes and chain lengths, which may cause the apparent inability of Cr. modiglianii to discriminate Ca. rufifemur nestmates from allocolonial Ca. rufifemur workers of the same chemical variety.

No MeSH data available.


Related in: MedlinePlus