Leea - An Insect Haven

Leea inflorescence - Not all flowers bloom at the same time

The clouds roared and rain poured in Mumbai on the evening of 2nd June 2011. The weather is still (extremely) sultry, but after a long summer, the cloud cover is beginning to take over the sun. As the pre-monsoon showers bathe the ground and wash the dusty leaves, many little flower buds will bloom into a grandeur celebration. While the rain will provide a respite for shriveled roots and thirsty throats, the flowers will provide a nutritious feast for the nectar lovers. It is that time of the year for one of the favorites of all the butterflies, bugs, beetles, ants, bees and wasps – Leea.

Leea is a genus of a perennial shrub in the family Leeaceae (or Vitaceae, according to Angiosperm Phylogeny Group II System). There are around 34 species found in the Indo-Australian region and parts of Africa. About 10 species have been recorded in Mumbai’s forests – with L. indica and L. macrophyla being the most common. Both of these are easily distinguished from the shape of their leaves – L. indica possesses double- or triple-compound large leaves, while L. macrophyla has single large leaves. The flowering season begins by the end of June and beginning of July, and lasts until September.

Angled Pierrot

Although I’m not sure about the quantity of nectar, or any other nutrients present in these tiny flowers, they sure must taste delicious! And for this reason, Leea is renowned in the insect world. As Monsoon is just around the corner, let’s take an exclusive look at Leea, and a few other monsoon flora including the rival Lantana camara.

Flowers provide a rich diet to many animals, therefore it is not surprising to see some that are completely dependent on it as a primary source of nourishment. The largest numbers of species relying directly on nectar belong to the class Insecta. From a butterfly commonly associated with flowers, to a male Mosquito of a species known to spread malaria, everyone feeds on it. What makes Leea special is not only the nutrient it contains, but the time of the year it flowers, that is, when there is an abundance of mouths to feed. Leea, like many flowering plants, profits from its free buffet by getting pollinated in return – an important return of favour from the visitors.

A Great Eggfly and a Blue Tiger in the bar

And these visitors range from a wide variety of Orders. Butterflies are probably the first to be attracted to Leea as everyone – from Family Hesperiidae and Lycaenidae to Pieridae, Nymphalidae and Papilionidae make sure to pay a visit to the local Leea Bar. In the Hymenoptera world, too, almost everyone drops in. Ants usually scavenging on the ground, such as some Camponotus sp. easily find a way to the top of this shrub’s canopy – a meter high from the ground, as do the arboreal ones, such as the Crematogaster sp. Bees ranging from small Stingless Bee, to large Honey Bee (and an as yet unidentified bee) have been observed feasting/collecting nectar/pollen. Wasps such as Potter Wasp, Paper Wasp and Scoliid Wasp, all notoriously shy when approached closer for photography, have been observed even more closely on Leea.

A Bee (which?) on Leea

All of these insects are known to feed exclusively on nectar. There are some you wouldn’t expect to see who also have a knack for this sugary treat. Bugs in the Order Hemiptera, such as the Shield Bug (Superfamily Pentatomoidea) pierce the flowers (and not the stem). Assassin Bugs (Family Reduviidae) have been noticed lurking beneath the inflorescence. A variety of Beetles and Weevils, such as Click Beetle, Fireflies, Net-winged Beetles and Leaf Beetles have been seen on the flowers – probably feeding on nectar as well as other flower parts. Flies (Order Diptera) also love to lap up the juices, with Bottle flies (Calliphoridae) and various Muscid flies visiting the flowers, but, surprisingly, not in large numbers.

It is truly marvelous to observe so many insects feeding co-operatively on a single plant, making Leea Bar a safe place to drink and enjoy – but nothing is as decent as it looks. There are dangers lurking in the downtown surrounding Leea – beneath, or even on top of the flowers. Predators such as Assassin Bugs and Praying Mantises stalk the streets day and night.

A Lynx Spider on Leea inflorescence

There are also arthropods of the fourth kind (I mean with four pair of legs) – Arachnids, the commonest observed on the flowers are Lynx Spiders (Family Oxyopidae), besides the wandering Jumping Spiders (Family Salticidae) and stealthy Crab Spiders (Family Thomisidae) and sometimes an odd Orb-weaver (Family Araneidae). I have also observed Harvestmen (Order Opiliones) on the inflorescence – but I’m not sure if they were feeding on the plant or predating on the visitors.

It’s quite something to count all the Families as well as species that visit Leea. In a study conducted by my friend on insects that feed on Leea indica, she found about 20 species of butterflies (adults) feeding on its flowers. In all the amazing flora diversity in Mumbai, the only plant that may openly challenge Leea is Lantana camara – an exotic species introduced as an ornamental plant from the American tropics.

Tailed Jay visits Lantana as much as it visits Leea

Lantana is equally, if not more or less, attractive to nectar feeders, and the most common animals seen on Lantana are butterflies and birds. While Leea undoubtedly wins in the diversity of species feeding off its nectar, Lantana probably gets more hits from number of visitors (of the same species or Order) – perhaps because the flowers are brightly coloured and bloom for a longer period of time. It must also depend on the shape of the flowers, which are easily accessible to those with a long proboscis.

Blue Tiger butterfly on Cockscomb

Other flora to look for, especially for insects this Monsoon are – Balsam (Impatiens sp.) which are good to observe bees, flies and Crab Spiders; Pea (Vigna sp.) are commonly visited by butterflies; Tridax is an excellent herb to observe butterflies; as well as Cockscomb (Celosia argentea) and Commelina sp. among others.

It will be interesting to make notes of the feeding activities of different animals on Leea and other monsoon flora. If you’re willing to keep notes, do share your observations which will help us understand more about these plants’ role in the ecosystem within the city limits and beyond.

________________________

Also, I went for Tree Plantation conducted by WWF MSO and Keshav Srishti, Uttan on the eve of World Environment Day. We planted about 25 native saplings on a reclaimed land. The event was a great success attended by toddlers, students as well as seniors. Unfortunately, my hands were too full of manure and wet soil to take pictures, but here’s one blurry picture of a Vine Snake one of us spotted on the way out:

Vine Snake on a Mango tree!

Happy World Environment Day!