The Tisa Mayfly (Palingenia longicauda)
The Tisa Mayfly (Palingenia longicauda) is the largest mayfly species
in Europe, males measuring up to 12 cm (5 inches) from head to tail.
This long-tailed mayflies are aquatic insects which belong to the
Ephemeroptera order. Their larval stage usually lasts three years. The
adults are short-lived: once fully matured, they have roughly three
hours to mate and then die. Male Tisa Mayflies are unique among the
winged insects in that they molt one more time after acquiring
functional wings. This second-to-last winged instar is usually a matter
Typically, all Tisa Mayflies mature at once, and for about a week in mid June, they will be everywhere after 5.00-6.00 PM, dancing over the river in large groups, molting on trees or on the ground, or resting on every available surface, including onlookers. This natural phenomenon with varied intensity is called Tisa blooming. Once they fully mature (after their second molting into a winged state), males have only a few hours to find females and mate before both sexes die. Squadrons of mature males will skim over the river's surface, seeking females.
After mating, the female mayflies start a compensation flight up the river, to ensure that the eggs laid on the river will sink down to the bottom at the place where their parents emerged. After about 45 days, the eggs hatch into larvae, which remain buried in the mud for three years, until they emerge and molt into adults.
The mayflies are pollution-sensitive animals, thus if they are in or around the water, the water should be of a good quality. Besides being environmental indicators, the mayflies are also a favorite food of many fish, and consequently a favorite bait used by fishermen.
The Tisa Mayfly has become extinct in many European countries, and now it can be seen only in N Serbia (Vojvodina province) and Hungary.
See more images of this interesting natural phenomena in photo gallery »