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Madagascar.

Insects, Spiders and

other invertebrates.




With approx. 100,000 species of  insects (and growing daily) Madagascar is richly endowed with creepy crawlies. Finding the information on Malagasy insects has been quite difficult for two reasons. Firstly there is the fact that my knowledge of insects is quite limited and secondly because the work of cataloging them all is basically an ongoing project. I have been trying to name the few we have photographed with little luck but hopefully those with better knowledge will give me the correct names.
There is no endemic insect family in Madagascar. It shares many family and generic groups with mainland Africa and it is only as you delve into the species themselves that the differences begin to appear. 90-100% of Malagasy insect species so far named are endemic to the island, which is extraordinary by any means. Many of the insect species Madagascar shares with mainland Africa are known to be strong fliers so it is no surprise to see that they made their way to Madagascar and then evolved to suit their new habitat. Malagasy species show distinct adaptations, the Mayflies for example being some of the largest in the world.

Ants.
 I do know that there are 418 species and subspecies of ants on the island and this is based on the great work being done at Antweb.org here. Even they admit that two thirds of Malagasy ants have still to be described!

Spiders.
 Spiders are present in abundance and some of them are big. Again work is ongoing on the list of Malagasy spiders and the place to watch for that is here at the California Academy of Sciences. They also have a large list of  Cerambycidae (beetles), Neuropterida (Lacewings and others related) and Sphecidae (Thread waisted wasps).
There are currently about 470 endemic species of spider named but the experts expect this to top 3,000 eventually.

Millipedes.
 Thomas Wesener is working on Malagasy millipedes. Here. Madagascar has some of the largest millipedes in the world with 160 species known of which 127 of these are probably endemic. Tropical millipedes are a very understudied group.

Butterflies and Moths.
  311 species of butterfly with 74% of these endemic to the island and around 4,000 species of moths. Much work needs to be done on this group. Many species are known from only one collected specimen and some of these are quite old.

Odonata. Dragonflies and Damselflies.
Of the 52 genera represented on the island, 12 are endemic.  Of the 181 named species and subspecies, 132 are endemic. Most genera and species are derived from mainland African species (strong fliers)  but at least 2 genera are more closely related to species in South East Asia and the Pacific Islands.

Termites.
Contrary to termites elsewhere, the Malagasy ones mainly live in dead wood and the few species that do build earth mounds build ones substantially smaller than elsewhere in the tropics. The studies which have been done on the termites indicate that the current fauna is intermediate between a continental and oceanic population. Many of the Malagasy genera occur elsewhere across tropical oceania and have spread on driftwood. Whether these species originated on Madagascar and drifted to new islands or drifted to Madagascar from other islands is unknown at present......I think. It looks like there is loads of work for termite fans out there.

Fleas.
 About 77% of Malagasy fleas are endemic to the island and are most closely related to those on mainland Africa.  Some fleas have been widely studied in Madagascar mainly because they carry bubonic plague which still occurs in the wild. So the fleas which live on introduced rats have been well studied whereas those that live on endemic animals are less studied and known.

Mosquitoes.
Another group of insects whose study has been based around the their ability to spread disease. Malaria is a big problem in Madagascar and the mossies bite at the first chance. 178 species have been described with about 45% of these endemic to the island.

Diptera. True Flies.
This is an enormous group worlwide and on Madagascar it is no exception. 80% of the species so far studied are endemic to the island but what is staggering about Madagascar is the sheer density of species and genera per square kilometre in comparison to tropical Africa. There are 3 times the amount of species and 9 times the amount of genera compared to the neighbouring mainland. Insect traps in Madagascar consistently catch new species and genera of Diptera. When fully catalogued they may constitute more new species to Madagascar than all the other orders of animals combined. What research has been done so far has shown some of the most spectacular environmental adaptions anywhere in the insect world. Madagascar's diverse habitat has once again provided a vast natural experimental laboratory for us to study or destroy. The choice is ours.

Other Interesting Invertebrates.

Scorpions.
There are about 40 species of scorpion so far found on Madagascar and all are endemic. As research coverage on the ground increases, and the methods of collection  become more sophisticated the number of species will increase accordingly. The ratio of scorpion species to endemism  is the highest in the world.

Freshwater  Shrimp.

Madagascar has a rich fauna of freshwater shrimp and they form a traditional part of the Malagasy diet. Atyids are small 35mm shrimp known as patsa by the locals and are caught in sqaure nets held at the end of a long pole.They are then dried and used to embellish sauces. Some of the cave dwelling shrimps have their nearest relatives in Australia's Northern Territory. Of the 40 or so species of freshwater shrimp currently known and studied, 24 are endemic to Madagascar.

Freshwater Crayfish.
These are a very interesting group as there are no freshwater crayfish in mainland Africa or India at all.  The closest living relatives to the Malagasy crayfish are in Australia and South America. This distribution mimics dinosaur fossils from Madagascar which also have a similar link. It lends to the theory that when Madagascar split from Africa, a landbridge existed for some time afterwards which joined it to Australia which was also still joined at the time to South America via a landbridge through Antarctica. Madagascar crayfish are under threat due to their use a food source. Some restaurants in the Central Highlands specialise in crayfish. The locals who collect for these restaurants say they now have to travel further and further afield to catch crayfish and their numbers are down when they do find them. There are 6 species currently know in Madagascar.

Freshwater Crabs.
12 species are known to occur and all are endemic to the island. Unlike the crayfish, the Malagasy crabs are closely related to their mainland African counterparts. More species are expected to be discovered on further research. Two of the known species grow to 70mm across the carapace



Please click on the photos link opposite left to see our images of Insects in Madagascar.

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