After photographing Female Plain Tiger, I was in the hunt for the Male Plain Tiger. As the Plain Tiger is known to be parasitized at least occasionally by Spiroplasma bacteria which selectively kill off male hosts, a subsequent scarcity of Plain Tiger males might have led to this hybridization and the evolution of the new species Dorippus Tiger (Danaus dorippus). From the color pattern of Danaus dorippus, it can be assumed that the ancient lineage had no black apex on the forewings, a character which is still absent in Danaus dorippus.
I was not disappointed as after few hours of hunting for a male, I got a bonus catch of mating plain tigers. I was using my Canon EF 300mm f/2.8L IS USM on Canon EOS 1D Mark IV fitted with Canon EF 1.4x III Extender. After adjusting myself to a suitable position where these butterflies were clearly visible I patiently waited for long time to get that momentary glimpse of open wing. During mating period these butterflies hardly ever open their wings.
After few minutes I could witness a very brief glimpse of Male Plain Tiger opening his wings. The male Plain Tiger is smaller than the female, but more brightly colored. In addition, male plain tigers have a number of secondary sexual characteristics. The male has a pouch on the hind-wing. This spot is white with a thick black border and bulges slightly. It is a cluster of specialized scent scales used to attract females. The males also possess two brush-like organs which can be pushed out of the tip of the abdomen.
Within few minutes I found another male who came looking for female and found this pair. He was spiraling over the pair and each time he came near the mating male, that male used to open its wing to ward him off. Female was quiet and unmoved during any of these advances. This went on for a long time till both male and female started reacting (see the first picture on the top). After that threat the attacking male went away disappointed.
The life cycle of a butterfly is dependent on its ability to find a mate and reproduce. The adult butterfly spends much of its time in search of a mate. Insect flight is characterized into two groups, trivial flight and dispersal flight. A trivial flight involves behavior related to daily needs of the butterfly, while dispersal flights are related to migration. Mate locating behavior in male butterflies is also separated into two main categories, patrolling and perching.
Patrolling species fly through their habitat in search of females. Flight is almost constant in this type of behavior where the male uses the females scent to locate her. Wing color is also important with patrolling males. They instinctively know what the female’s wing pattern looks like and search for that pattern. The male is more attracted to the females predominant wing color than any other color, thus a male may be tricked into following an inanimate object that is the same color as the female.
In perching butterflies the males await receptive females in certain places and at certain times. A potential female flies past the male, who then darts out to investigate. If it is a suitable female then mating ensues, if not, the male will return to a roosting area to await another potential female. Females seem to know where the males will be perched; hence it is common to see them fluttering in that habitat waiting for a male.
Roosting areas are genetically fixed in each species and both sexes instinctively go to them. Anything passing through the habitat where a male is perching is likely to attract the male. It is very common to see male butterflies investigating other insects including other butterfly species, flies, dragonflies, bees, and wasps. If the male discovers another 2 male of its species a duel will result. Both males will fly in a spiraling manner upward until one, usually the primary resident, will fly back to its perch. This gives the false impression that butterflies are territorial. This is not true since the males are actually investigating whatever object they see in its view to determine if it is a female. Each of these factors play a vital part in mate-locating behavior and ultimately species perpetuation.
The main purpose of courtship is to determine if both individuals are healthy members of the correct species. In order for this to occur, adults use color pattern or odor to accept or reject an individual. Many species identify each other with visible colors or ultraviolet patterns seen on the wings. Ultraviolet is used by many butterflies to both identify mates and nectar bearing flowers.
If a female is ready to mate the male will wait until she lands and then will quickly mate with her without any complicated mating ritual. It is also possible that the two may fly in a zigzag pattern or hover beside each other before mating. Pheromones or perfumes are transferred at this time and a fluttering of the wings may occur. Wing fluttering may be an indication of mate acceptance or rejection. Special wing scales with glands contain the pheromones.
Sometimes the scales resemble brush-like tufts of hair on the wings and others resemble ordinary wing scales. If the male carries a pheromone he will usually flutter above the female to release his scent. The mating process lasts from 15 minutes to 3 hours, depending on the species. Small butterflies have a short mating span and large butterflies have longer ones, however, mating time also varies in cooler weather. Both sexes can mate more than once.
The male needs up to 8 hours after mating to produce another spermatophore to mate again, and the female may, in some species, be able to mate almost directly after she has finished with a previous mate. Females in most species are temporarily prevented from mating again due to the spermatophore in her mating tube. As soon as the spermatophore is digested she can mate again. The spermatophore has been the subject of many recent studies, and may play a key role in shaping the characteristics of the butterfly mating system.
If a female is unreceptive or has just mated, courtship will be more complicated. Females may perform several moves to discourage a male. For example, females may undergo a “rejection dance” in which she flies vertically into the air and then downward quickly so that the male cannot follow her or gets discouraged and leaves. Unreceptive females may also mimic a male when being approached by a perching male of her own species, this also discourages the male from attempting to mate. Females may simply crawl, fly away, or move her abdomen in between her wings so that a male cannot join with her.
Some species have specialized glands in the female called stink clubs to repel males. The stink clubs waft a foul-smelling chemical that males do not like. Stink clubs are engaged after a female has mated. Rejection in females serves a purpose. As stated above, newly mated females may not need to mate again or unreceptive female may try and encourage aggressive males to mate with her in order to obtain the best genetic material. It is important to realize that the female butterfly is not aware of this, it is simply natural selection at work. Most unreceptive females however may not mate at all.
Females in general either mate right away or not at all. After mating the female butterfly must find a suitable host plant to lay her eggs. She may almost be able to lay her eggs directly after she has mated, or she may wait several days. Some species can lay as many as 1,000 eggs but one to two hundred or less is more common. The female will fly slowly and land on many plants while searching for her host. The legs contain special clumps of hair-like taste organs and she will use these to test the plants and identify it. Observing this behavior in females may enable one to find the host plant in a habitat.
When the female has found a host plant she will begin to flutter around it and curve her abdomen downward and forward to lay an egg with her ovipositor. The ovipositor has very sensitive hairs that probably taste the plant as well. Females that lay clusters of eggs may take a long time, an hour or more, and visit the same plant repeatedly. Eggs are usually laid singly and glued to the host. Eggs laid on leaves are placed on the underside in most cases and other females will avoid that leaf when searching for places to lay their eggs. Most butterflies lay their eggs on plants that can be eaten by the larva. This is due to the larva’s poor ability to find food. They see weakly and travel slowly. In most cases if a larva does not find its host plant, it dies. Death can also occur if the larva eats an unsuitable plant. Some however do lay their eggs haphazardly on anything around the host plant.