Archispirostreptus gigas

Introduction (SAM COOK)

Archispirostreptus gigas (A. gigas), commonly known as the Giant African Millipede, are one of the world’s largest terrestrial invertebrates (Carwardine, M. 2008) and are found along the east coast of Africa (Figure 4). They can grow to a length of 320mm (Vladimir, S. et al. 2013) ad a diameter of 20mm (Enghoff, H. 2014). These phyt

ophagous, nocturnal diplopods are black in colour and, like all millipedes, have 2 pairs of legs on each segment of their body averaging about 100 legs for each A. gig

as. The first segment comprises of two antennae, two compound eyes and a mouth. In the wild these millipedes have a life-span of around 7 years and prefer dark damp areas, often burrowing in a wave like motion through organic matter (Rosamond Gifford Zoo. 2006).

Interesting Facts (SAM COOK)

Figure 4 – distribution of giant millipedes in Africa. Archispirostreptus gigas are represented by the black area. Vladimir. (2014) The giant African millipede, Archispirostreptus gigas (Diplopoda: Spirostreptida), a model species for ecophysiological studies. Available at: https://www.semanticscholar.org/paper/The-giant-African-millipede-%2C-Archispirostreptus-(-Vladim%C3%ADr/3e0ce2713031fc82a99c9c576fada4ef61c61989 (Accessed 22 November 2019)
  • A. gigas have a symbiotic relationship with mites that live on their exoskeleton and legs. The mites eat debris off of the millipede’s exoskeleton keeping it clean, and in return they have a home and food (Rosamond Gifford Zoo. 2006).
  • Diplopodia has a long evolutionary history dating back 428 million years ago. A fossil of a similar species (Pneumodesmus newmani) has been identified as a relative due to the presence of spiracles which proves they were terrestrial (Wilson, M.H. and Anderson, I.L. 2004).

Reproduction (SAM COOK)

Archispirostreptus gigas are a progoneate species meaning their genital opening is in the anterior region of the body (Carwardine, M. 2008). Mating behaviour involves meeting, courting, insemination and release and often takes around 35 minutes (Vladimir, S. et al. 2013). Seasonal changes affect their mating cycle.  It was found that simulating a short period of drought followed by increased moisture would trigger egg laying. Because of this response to moisture this animal’s mating season occurs during spring and autumn. During courting, the male A.gigas uses his legs to stimulate the female by walking beside her. If the female is interested she will allow him to move underneath her; at which point they wrap themselves together and the male deposits his sperm on the female (Rosamond Gifford Zoo. 2006). A few weeks after mating (Rosamond Gifford Zoo. 2006), the female A.gigas will transfer the sperm to her eggs and deposit them into the substrate (Vladimir, S. et al. 2013). Each egg is contained in a separate capsule which is believed to protect them from desiccation (Vladimir, S. et al. 2013) and predators (Rosamond Gifford Zoo. 2006). Some eggs, however, have no capsule (Figure 5). They will hatch after around 3 months and during this time the female may guard the eggs, although after hatching they will be abandoned (Rosamond Gifford Zoo. 2006). All millipedes are anamorphic (Carwardine, M. 2008), although the morphological changes during ontogenesis has not been fully described yet (Vladimir, S. et al 2013).

Figure 5. Egg of A. Gigas lacking soil capsule
Vladimir, S. Et al. (2013) ‘The giant African millipede, Archispirostreptus gigas (Diplopoda: Spirostreptida), a model species for ecophysiological studies’. Pp. 145-152. no. 77 Available at: file://windows/Myfiles/H03D2789/W9256357/The%20giant%20african%20millipede,%20a%20model%20species.pdf (Accessed 22 November 2019)