What wings dare

On what wings dare he aspire?
What the hand, dare seize the fire?

The Tyger (1794) William Blake

Milkweed butterflies, like common crows (Euploea core) and common tigers (Danaus genutia), lay eggs on trees full of toxins. The newly hatched caterpillars then feed on the leaves of these plants and concentrate the toxins in their bodies. The toxins remain through their metamorphosis into butterflies, and make them undesirable prey. I’d assumed that just as they lay eggs on different plants, the adults must take nectar from different plants. I was surprised to find many individuals from both species feeding on one plant. I suppose that there are species of plants whose nectar attracts one or the other, but not both, species of butterflies. Otherwise the crows and tigers would be in competition. There’s nothing wrong with competition, but one eventually wins, and the other has to find a less desirable range. There is no evidence for that happening to one of these species.

A rich ecosystem is full of creatures utilizing every resource, and individuals of one species are a resource for another. The caterpillars are parasites on their host plants, but the adults have reached a sexual mutualism with nectar yielding plants. The plants require butterflies for fertlization, and the butterflies are unable to lay eggs without the sugar that the plants supply. These butterflies have their own parasites: tiny flies (tachinids) and wasps (chalcids). They lay their eggs in caterpillars. The parasitic maggots hatch and eat their hosts from inside. Although I haven’t seen the parasites yet I remain hopeful and ready with my camera; the adult flies and wasps are big enough that I could photograph them. On the other hand, the only symbiotes of these two which have been studied are really tiny: bacteria from a genus called Wolbachia which live entirely inside the cells of the butterflies and influence their reproductive strategies. There is no chance that my camera will ever catch these.

The jungle was full of such lovely small things. The photo of the spider web that you see was taken on a path called thandi sadak (cool road). It was surrounded by fields full of this plant that some would recognize immediately; they grow wild across the hills and are a target for foragers. The spider itself was too small to be seen. There’s a lot of literature on how cannabinoids influence spiders. You can actually see a typical example here: some of the space between the spokes have not been filled in. I’m not sure that spiders munch leaves, but they could be eating insects which have taken up toxins from the plant. Although chital (Axis axis, spotted deer) grazed in neighbouring patches of grass, they did not venture into fields of Grass.

Less spectacular than the crows and tigers, but equally abundant, were these common sailors (Neptis hylas). They have an interesting flight: a couple of wing beats and then a long glide, then again a wing beat or two. I would like to weigh them, because the flight pattern could mean that the wings are large compared to the weight, like a glider’s. They are not milkweed butterflies, and there is no record of them being distasteful or poisonous. That’s why it puzzles me that there are so many of them in the jungle, and there seem to be no predators. A low body weight could also imply that they are too small a portion to be worthwhile for birds to hunt. Perhaps also their fecundity, eggs hatch multiple times a year, keep their numbers high although they are edible.

A dark shape flew into the leaf-litter below the where the sailor was sunning itself. The moment it stopped moving it disappeared. I searched the ground and couldn’t see anything. Then there was a tiny movement in the ground, and I could focus on it. This was a Prosotas butterfly, possibly the common lineblue (Prosotas nora). I always have to look at the lineblues carefully to figure out the species, and the strong sunlight with dark shadows, and the odd angle I was looking at it prevents me from making a firm identification. But this is was a happy sighting: here was a non-poisonous butterfly which took good care to camouflage itself. Even in the photo, you could mistake it for a dried leaf if you just glance across it quickly.

The buffer zones of these protected forests are set up to attract large numbers of eco-tourists, so that residents have a stake in keeping the jungle protected. But since the average person is interested only in large animals, tigers or elephants and deer, there is little opportunity for those interested in small things like insects to observe them. From the back of a jeep I saw only the small creatures that I already knew. Seeing the familiar in a new setting can always show you new behaviour and raise new questions. So I found myself happy even with these limited opportunities.