Common name: Leaproach
Derivation of scientific name
Saltoblattella is the Latin translation of “jumping small cockroach” and montistabularis is derived from “Mons tabularis” the old Latin name for Table Mountain in Cape Town where the species is endemic.
The leaproach (Saltoblattella montistabularis) is the world’s only known jumping cockroach and it is endemic to the Fynbos biome of Table Mountain, South Africa. This remarkable cockroach shows parallel evolution with grasshoppers in terms of body plan and adaptation for a jumping form of locomotion. These adaptations include 1) wide protruding eyes that afford it well-developed vision, 2) a second joint at the base of the antennae that helps to stabilise it in airflow during jumps, and 3) highly modified limbs (femur and tibia) and associated muscles that facilitate the jumping motion. Its small and restricted range makes the species vulnerable to changes in its habitat, especially given the fact that little is known about its biology.
How to recognise a leaproach
The leaproach is a small (6–10 mm long), light brown cockroach with pale stripes down the sides of its body. The hind legs are large and stick out of the sides of the body like those of a grasshopper. The leaproach has long antennae and large, round eyes. Females can be observed carrying an egg case—a brown, seed-like package that protrudes from the end of her abdomen.
Getting around
The leaproach jumps from stem-to-stem among plants and grasses; much like a grasshopper. It can also scuttle short distances like a normal cockroach does. The leaproach is able to jump distances up to 50× its body length. It achieves this by using its long and muscular hind legs, and it has an elastic protein in its knee-joint that aids in jumping and storing energy. Unlike other cockroaches it has lost the ability to fly and has no functional wings.
Communication
It is not known how the leaproach communicates, but like other cockroach species it is likely to use pheromones to communicate with other individuals of its species.
Distribution
The leaproach is currently only known to be found in the Fynbos biome of Table Mountain National Park, in Cape Town, South Africa.
Habitat
The leaproach is known to occur in high altitude mountainous terrain with heathland vegetation and is common among grasses and sedges.
Food
The natural diet of the leaproach is largely unknown, but in captivity it feeds on a range of plant-based foods. It has also been observed to feed on grasshopper droppings.
Sex and life cycle
Sex: Female leaproaches will copulate with male roaches and produce eggs that are kept inside a hard, protective case that looks like a small seed. Females will carry this case around for a short time until the outer case hardens, then she will drop it on the ground.
The big picture
Friends and foes
The leaproach lives amongst grasshopper species and other plant-dwelling and feeding insects. It is no doubt preyed upon by birds and other insects, such as praying mantids.
Smart strategies
The anatomy of the leaproach is well adapted to jumping locomotion. It has large eyes for accurate jumping from twig-to-twig and for detecting predators. Unlike most other cockroaches, it is active during the day. It also has an extra joint at the base of the antennae that helps stabilise and protect the antennae during jumping and landing. It has long and muscular hind legs that have resilin, an elastic protein, in the knee-joints. The elastic protein aids jumping by storing energy during muscle contraction and releasing it in a catapult action that propels the jump.
Poorer world without me
Cockroaches play a vital role in nutrient decomposition and breaking down of plant material. They also form a major part of birds’ and insects’ diets.
Conservation status and what the future holds
The leaproach is the only known jumping cockroach and is only known to exist in a protected area inside the Table Mountain National Park. Its small and restricted range makes the species vulnerable to changes in its habitat, especially given the fact that little is known about its biology. There is therefore a need for more research to generate information on various aspects of this species’ biology. For example, more species of leaproach are likely to occur outside the park in adjacent areas of the Fynbos Biome. Information on species diversity and areas of occurrence can then be used to inform and direct management policies.
Relatives
There are approximately 4 500 known species of cockroaches in the order Blattodea, of which 700 occur in South Africa. Blattodea comprises eight families, namely: Blattidae (wood cockroaches); Polyphagidae (sand cockroaches); Cryptocercidae (brown-hooded cockroaches); Nocticolidae (associated with caves and termites); Blattellidae (wood cockroaches); Blaberidae (giant cockroaches); Lamproblattidae (a small family of South and Central American cockroaches) and Tryonicidae (that occurs in Australia, New Caledonia and New Zealand).
Currently there is only a single species of leaproach known and it is the only member of the genus Saltoblattella, which has been placed in the family Blattellidae. The exact position of the genus within the family Blattellidae is not clear, however, and it was provisionally placed in Blattellinae. This taxonomic uncertainty is because the leaproach has a large number of unique characteristics besides adaptations to jumping that are not in agreement with known characteristics of subfamilies in Blattellidae. Further research is required to clarify the phylogeny in the family Blattellidae.
While it is not evident why the strange behaviour of the leaproach should have evolved only in one type of cockroach, and why this should have happened in the Fynbos Biome, the evolutionary shift is most likely an adaptation to more efficient locomotion in a vertically stratified habitat, such as stands of grasses and sedges.
Scientific classification
Leaproach: (Saltoblattella montistabularis)
Order: Blattodea
Family: Blattellidae
Genus: Saltoblattella
Species: S. montistabularis
References and further reading
- Bohn, H., Picker, M.D., Klaus-Dieter, K. & Colville, J.F. 2010. A jumping cockroach from South Africa, Saltoblattella montistabularis, gen. nov., spec. nov. (Blattodea: Blattellidae). Arthropod Systematics & Phylogeny. 68,1: 53–69.
- Picker, M.D., Colville, J.F. & Burrows, M. 2012. A cockroach that jumps. Biology Letters. 8: 390–392.
Author: Jonathan F. Colville
Applied Biodiversity Research, SANBI
February 2014