Geographical variation in host-ant specificity of the parasitic butterfly Maculinea alcon in Denmark

TY - JOUR

T1 - Geographical variation in host-ant specificity of the parasitic butterfly Maculinea alcon in Denmark

AU - Als, Thomas Damm

AU - Nash, David Richard

AU - Boomsma, J. J.

PY - 2002/8/1

Y1 - 2002/8/1

N2 - 1. Maculinea alcon uses three different species of Myrmica host ants along a north-south gradient in Europe. Based on this geographical variation in host ant use, Elmes et al. (1994) suggested that M. alcon might consist of three or more cryptic species or host races, each using a single and different host-ant species.2. Population-specific differences in allozyme genotypes of M. alcon in Denmark (Gadeberg Boomsma, 1997) have suggested that genetically differentiated forms may occur in a gradient across Denmark, possibly in relation to the use of different host ants.3. It was found that two host-ant species are indeed used as hosts in Denmark, but not in a clear-cut north-south gradient. Furthermore, specificity was not complete for many M. alcon populations. Of five populations investigated in detail, one used primarily M. rubra as a host, another exclusively used M. ruginodis, while the other three populations used both ant species. No population in Denmark used M. scabrinodis as a host, although this species was present in the habitat and is known to be a host in central and southern Europe.4. In terms of number of parasites per nest and number of nests parasitised, M. rubra seems to be a more suitable host in populations where two host species are used simultaneously. Host-ant species has an influence on caterpillar size but this varies geographically. Analyses of pupae did not, however, show size differences between M. alcon raised in M. rubra and M. ruginodis nests.5. The geographical mosaic of host specificity and demography of M. alcon in Denmark probably reflects the co-evolution of M. alcon with two alternative host species. This system therefore provides an interesting opportunity for studying details of the evolution of parasite specificity and the dynamics of host-race formation.

AB - 1. Maculinea alcon uses three different species of Myrmica host ants along a north-south gradient in Europe. Based on this geographical variation in host ant use, Elmes et al. (1994) suggested that M. alcon might consist of three or more cryptic species or host races, each using a single and different host-ant species.2. Population-specific differences in allozyme genotypes of M. alcon in Denmark (Gadeberg Boomsma, 1997) have suggested that genetically differentiated forms may occur in a gradient across Denmark, possibly in relation to the use of different host ants.3. It was found that two host-ant species are indeed used as hosts in Denmark, but not in a clear-cut north-south gradient. Furthermore, specificity was not complete for many M. alcon populations. Of five populations investigated in detail, one used primarily M. rubra as a host, another exclusively used M. ruginodis, while the other three populations used both ant species. No population in Denmark used M. scabrinodis as a host, although this species was present in the habitat and is known to be a host in central and southern Europe.4. In terms of number of parasites per nest and number of nests parasitised, M. rubra seems to be a more suitable host in populations where two host species are used simultaneously. Host-ant species has an influence on caterpillar size but this varies geographically. Analyses of pupae did not, however, show size differences between M. alcon raised in M. rubra and M. ruginodis nests.5. The geographical mosaic of host specificity and demography of M. alcon in Denmark probably reflects the co-evolution of M. alcon with two alternative host species. This system therefore provides an interesting opportunity for studying details of the evolution of parasite specificity and the dynamics of host-race formation.

KW - JALMENUS-EVAGORAS

KW - clumped distribution

KW - LARVAE

KW - Gamma

KW - NESTS

KW - Maculinea alcon

KW - social parasitism

KW - LARGE-BLUE

KW - POLYMORPHIC GROWTH

KW - LYCAENID BUTTERFLIES

KW - geographical variation

KW - ATTENDANT ANTS

KW - host specificity

KW - LEPIDOPTERA

KW - SOCIAL PARASITE

KW - REBELI

KW - Myrmica

KW - PDF

M3 - Tidsskriftartikel

SN - 0307-6946

VL - 27

SP - 403

EP - 414

JO - Ecological Entomology

JF - Ecological Entomology

ER -