Unlikely friends: ants and butterflies

Hypolycaena phorbas male
Black-spotted Flash (male) perched on a green-ants’ nest

Walking back down the hill for Tegoora Rock lookout (previous post) I spotted a green-ant nest with – surprisingly – a butterfly perched on it. Living dangerously, surely? Perhaps not.

I had vague memories vague of mutually beneficial partnerships between butterflies and ants so I looked them up when I got home. The butterfly guide books (and sites) generally just note the “attendant ant” species and the food plants, e.g.

The caterpillar is aways attended by the green ants :

It usually hides by day under a leaf, and feeds by night on the leaves, young shoots, buds, and flowers of a wide variety of plants, including :

The Caterpillars pupate on the stems of the food plant, often in groups, head down.

That’s from the Herbison-Evans and Crossley site’s page about the Black-spotted Flash, which they call the Common Tit. (Perhaps it is “common” because it has so many host plants?)

The best short explanation of the relationship’s benefits I found was this:

The butterfly family Lycaenidae (including the Riodinidae) contains an estimated 30% of all butterfly species and exhibits a diverse array of life history strategies. The early stages [i.e. caterpillars] of most lycaenids associate with ants to varying degrees, ranging from casual facultative coexistence [i.e. they help each other but don’t need each other] through to obligate association where the long-term survival of the butterfly is dependent on the presence of its attendant ants. Attendant ants guard the butterflies against predators and parasites during their vulnerable period of larval growth and pupation. The caterpillars, in return, reward the ants by providing attractive secretions from specialized glands in their cuticle.

That’s the introduction to a thesis, Ant Association and Speciation in Lycaenidae (Lepidoptera): Consequences of Novel Adaptations and Pleistocene Climate Changes, by Rodney Eastwood (pdf here). The thesis itself is concerned with tracing associations between ant species, the butterflies they care for, and the butterflies’ host plants; I know a couple of people who would enjoy it but the general idea is enough for most of us.

An article by Eastwood (again) and Ann Fraser in Austral Ecology, “Associations between lycaenid butterflies and ants in Australia,” gives us some statistics:

Nearly 80% of the lycaenid species in Australia, for which the early stages are known, are recorded associating with ants and half of these are obligately ant-associated. … Lycaenids are recorded with five ant subfamilies …  All ant species that tend lycaenids spend at least some portion of their time foraging on vegetation to collect plant and insect nectar.

As I said in an earlier post, male butterflies often hang around their caterpillars’ food plants waiting for females to come and lay eggs, and it is quite likely that the one I photographed is doing just that. And if the ants recognise the caterpillars through chemical cues, the adult probably produces the same cues and will be safe on their nest.

Finally, here is the female of the species, which I photographed at the other end of the Common a few years ago.

Black-spotted Flash
Black-spotted Flash, female

 

Green-ants and their dinner

green-ants on wire fence
Green-ants on our garden fence

A chicken-wire fence forms the boundary between our garden and our neighbours. To the green-ants whose garden we share (that’s the way it feels at times), the fence is a convenient highway. The trio on the right were returning to the nest after a successful hunt when I saw them.

The prey is, I think, a fly. The ants are 8-10mm long, so the fly is only about 2.5mm – certainly not big enough to attract human attention in normal circumstances. I just happened to be there with my camera, on one of my periodic rambles around the garden, and took the photo without being aware of exactly what was going on. There’s always more to see!

 

Green-ant mating flight

Exactly three years ago I posted an article about the queen green-ants I saw on Magnetic Island the day before. They were the first I had seen, and I hadn’t seen any since then until I fished three or four of them out of my swimming pool this morning. They weren’t at their best after their swim so you will have to visit this page for photos.

I looked around my garden for living queens but failed to find any, so all I know of this emergence is that it happened some time in the last 24 hours. I would be interested to hear from readers who have seen more.

Green-ant mimic

Nearly a year ago I wrote about a bug which was doing a great job of pretending to be a black ant. This time I have one which similarly pretends to be one of our ubiquitous Green-ants. First, the real thing:

green ant
Green-ant – note the jaws

Now here’s the mimic …

green-tailed bug
Not as dangerous as I pretend to be

I noticed it mostly because the antennae looked vaguely wrong for an ant. Looking more and more closely, I could see (1) that the antennae curve smoothly backwards instead of having obvious elbows and pointing forwards, (2) the body is broader and (3) it has no jaws. In fact, it is the juvenile form (nymph) of a sap-sucking bug (Hemiptera), and like all its relatives it has a piercing tube, seen here tucked up against its chest, instead of jaws.

I thought it was a new species to me – I still get them occasionally in my own garden – but through Steve in Airlie Beach I found that I did know the adult but had been baffled by its difference from the nymph. Between us we have a complete sequence showing how it changes as it matures. The one above is the youngest and is the best ant-mimic; as it matures we get …

Green-ant mimic 6626

brown and green bug

ant mimic

Riptortus sp. 2762

The last of these four photos shows the adult, with its wings completely covering its abdomen. The middle two are courtesy of Steven Pearson, and I thank him for permission to use his photos and for identifying my ant mimic. It’s a Pod-sucking Bug, Riptortus sp., Alydidae, Hemiptera.

Riptortus serripes seems the most likely species since it’s the only one I’m sure has been identified in this region, but Brisbane Insects shows its nymphs mimicking black ants. Either we need to look out for another species or Brisbane Insects has confused R. serripes with its smaller cousin Melanacanthus scutellaris.