Conservation Biology of Lycaenidae (Butterflies) - IUCN
Conservation Biology of Lycaenidae (Butterflies) - IUCN
Conservation Biology of Lycaenidae (Butterflies) - IUCN
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workers <strong>of</strong> the same ant, Anoplolepis longipes (Jerdon) (Kitching<br />
1987).<br />
In many cases, relationships between myrmecophily or<br />
aphytophagy and oviposition patterns are not as clear as in<br />
Allotinus Felder & Felder. Laying eggs in clusters ('clustering')<br />
in many Australian <strong>Lycaenidae</strong> is strongly associated with<br />
obligate myrmecophily (Kitching 1981), but this is not the case<br />
for neotropical Riodininae, in which myrmecophilous species<br />
lay eggs singly (Callaghan 1986). In the latter group, clustering<br />
is associated with gregarious behaviour. Myrmecophilous<br />
riodinine larvae are solitary, and gregarious larvae are not<br />
myrmecophilous. The latter may be aposematic and conspicuous,<br />
so that their protection against many predators is a function <strong>of</strong><br />
their distastefulness. Many myrmecophilous larvae, in contrast,<br />
are rather cryptic, and accompanying ants may help to prevent<br />
them being attacked by predators and parasitoids.<br />
Such relationships between caterpillars and ants are thus <strong>of</strong><br />
central importance in considering the evolution and biology <strong>of</strong><br />
<strong>Lycaenidae</strong> and have attracted much attention.<br />
Myrmecophily and evolution in lycaenids<br />
Symbiosis with ants may have been an early development in the<br />
evolution <strong>of</strong> <strong>Lycaenidae</strong> (Eliot 1973), and both Hinton (1951)<br />
and Malicky (1969) suggested that ancestral lycaenids were<br />
myrmecophilous. Contrary to Pierce's (1987) conclusion that<br />
the distribution <strong>of</strong> myrmecophily in <strong>Lycaenidae</strong> does not reflect<br />
phylogeny, Fiedler (1991a, 1991b) believed that there was a<br />
strongly phylogenetic relationship present.<br />
However, there is some possible confusion over roles <strong>of</strong><br />
myrmecophily in lycaenoid evolution as their influences on<br />
Riodinines and the other taxa may be markedly different (De<br />
Vries 1991a). Not only are they the most common basis for<br />
suggesting ecological groupings in the family (Henning 1983),<br />
but the evolution <strong>of</strong> lycaenid diversity itself may also be<br />
involved. Pierce (1984) suggested that lycaenid diversity may<br />
reflect speciation in relation to other butterfly families, and that<br />
this could be influenced by larvae/ant associations in two<br />
important ways:<br />
1. Female lycaenids may adopt ants as oviposition cues<br />
(Fiedler and Maschwitz 1989, on Anthene emolus (Godart)) so<br />
that the presence <strong>of</strong> ants on a novel foodplant may induce a<br />
rapid host switch. Although few such 'oviposition mistakes'<br />
(Pierce 1984) may actually lead to range extensions, it may be<br />
more important for a given lycaenid to retain a particular ant<br />
association than a particular foodplant, and an increase in the<br />
number <strong>of</strong> ovipositions on different foodplants may increase<br />
the number <strong>of</strong> opportunities for subsequent speciation.<br />
Essentially, novel foodplant choices may be made by female<br />
lycaenids to an unusually high degree because they select for<br />
ants as well as for chemically and physically suitable foodplants.<br />
A 'new' hostplant may occupy a different ecological range<br />
from those utilised earlier, and population isolates could thus be<br />
formed.<br />
2. The general non-vagility <strong>of</strong> many lycaenids results in<br />
their occurrence in small, semi-isolated populations with rather<br />
5<br />
little regular genetic interchange between them. Pierce (1983)<br />
showed that a deme <strong>of</strong> the Australian Jalmenus evagoras<br />
(Donovan) may be restricted to a single Acacia tree, where<br />
males aggregate and compete for emerging females so that<br />
variability in male reproductive success effectively reduces<br />
population size further. Such patchy distributions (also noted in<br />
the North American Glaucopsyche lygdamus Doubleday: Pierce<br />
1984) occur in spite <strong>of</strong> apparent continuous foodplant availability<br />
and it is quite possible that they result from selection <strong>of</strong><br />
foodplant areas which are high in nitrogen, as well as having the<br />
required ants. Many myrmecophilous lycaenid larvae actively<br />
prefer nitrogen-rich foodplants and plant parts such as seed<br />
pods and flowers. This may be explained in part by the need to<br />
supply ants with amino acids as a 'nutrient reward' for tending<br />
the larvae (Pierce 1984).<br />
Larval feeding<br />
The overall importance <strong>of</strong> plant-feeding to caterpillars <strong>of</strong><br />
<strong>Lycaenidae</strong> differs substantially between different subfamilies,<br />
and those <strong>of</strong> some groups rarely take plant food. As far as is<br />
known, all species <strong>of</strong> Poritiinae and Lycaeninae are normally<br />
phytophagous. Some Curetinae are phytophagous. Lipteninae<br />
are also plant feeders, but are highly unusual amongst butterflies<br />
in that larval food usually consists <strong>of</strong> algae, fungi or lichens (see<br />
Cottrell 1984, for summary). Most genera <strong>of</strong> the two largest<br />
subfamilies, Theclinae and Polyommatinae, appear to be<br />
phytophagous or opportunistically carnivorous with varying<br />
degrees <strong>of</strong> dependence on prey. Maculinea van Eecke and<br />
Lepidochrysops Hedicke larvae are phytophagous when young,<br />
but the late instars are obligate predators <strong>of</strong> ant larvae. Other<br />
aphytophagous genera are noted in Table 1. Both Liphyrinae<br />
and Miletinae appear to be entirely aphytophagous, and the<br />
unlisted genera in Table 1 reflect ignorance <strong>of</strong> their larval<br />
biology, rather than known phytophagy. Liphyra Westwood<br />
and Euliphyra Holland larvae are probably specific feeders on<br />
early stages <strong>of</strong> tree ants (Oecophylla spp): their larvae are<br />
flattened and have a heavily armoured cuticle which enables<br />
them to withstand ant attacks. The pupa <strong>of</strong> Liphyra remains<br />
inside the last larval skin, which thereby functions as a puparium.<br />
Aslauga larvae are predators <strong>of</strong> Homoptera, at least as late<br />
instars. Eggs <strong>of</strong> Miletinae are typically laid near colonies <strong>of</strong><br />
Homoptera, including aphids, coccids and membracids and<br />
some, at least, are found on a wide range <strong>of</strong> different hostplants.<br />
Although the larvae are predominantly predators, some younger<br />
instars may also feed on honeydew or other insect secretions<br />
such as aphid cornicle secretions.<br />
Selection <strong>of</strong> foodplant species by phytophagous species,<br />
and their effects on foodplants, are difficult to study. Flower<br />
predation <strong>of</strong> a range <strong>of</strong> perennial herbaceous legumes by<br />
Glaucopsyche lygdamus in Colorado differed substantially<br />
between species (Breedlove and Ehrlich 1972), with either<br />
Lupinus or Theropsis being by far the most heavily attacked<br />
plant at each <strong>of</strong> a series <strong>of</strong> sites. On both plant genera, flowerfeeding<br />
can markedly reduce seed-set (Breedlove and Ehrlich<br />
1968,1972). Whereas G. lygdamus females select inflorescences