Adaptations & Interactions

 Adaptations  by Alex Crain

The H. haydeniana has a unique defense mechanism when it comes to deterring predators from eating them, they have the ability to produce the toxin, hydrogen cyanide (HCN).
When the yellow spotted millipede discharge hydrogen cyanide, the secretion oozes from the glands onto the millipede’s surface and coats the exoskeleton of the animal. On the sides of the millipede’s body are two-part glands that consist of a reservoir, which stores cyanohydrin and a reaction chamber where the cyanohydrin is broken down by enzymes to create hydrogen cyanide; as well as an aromatic molecule, benzaldehyde. The benzaldehyde is what gives the millipede’s their distinctive “bitter almond” smell. (Eisner et al. 1963) The millipede also metabolizes small quantities of the cyanide into β-cyanoalanine as well as asparagine; these two compounds may be used to detoxify small amounts of HCN that may leak into the milliped's body from the storage chamber housing the toxic chemical. (Rockstein 1978)
The millipede's secretions act as a topical irritant. As a general rule millipedes eject their toxins during the beginning stages of an attack, deterring their adversary before receiving major injuries. (Eisner and Meinwald 1966) Millipedes in contrast to centipedes do not have fangs, however the toxins that they secrete can cause erythema and brown/black pigmentation of the affected area.

Figure 1. This is what happens when toes are exposed to H. haydeniana's toxin

The pigmented lesions may last as long as several months. Though the effect of millipede toxins may look serious (on the skin) there are no major repercussions in humans. It is advised to immediately wash the effected site with alcohol or ether in order to dissolve the toxins. However if one were to get the toxin into their eye, seek immediate help from an ophthalmologist; in order to prevent blindness. (Hudson and Parsons 1997)

Interactions   by Sunita Nandihalli

H. haydeniana has both positive and negative interactions with other organisms. A negative interaction would be any interaction that either has a negative effect on the millipede or other organisms. A positive interaction would be a relationship (direct or indirect) that would have a positive effect on the millipede or the millipede and other organisms.
Let’s start out with negative organismal interactions: parasites and predators of H. haydeniana. Nematodes are one of the most common types of endoparasite among millipedes along with Dipterans (flies) in the family Phaeomyidae. Beetles, reptiles, birds, shrews, raccoons and other various mammals, spiders, amphbians, and even snails have been documented to prey on millipedes. (Sierwald & Bond 2007). However, when these animals get a taste for hydrogen cyanide, they’re most likely not going to want to get anywhere near H. haydeniana again.  Although these chemical defenses of H. haydeniana are able to keep most predators at bay, one specific beetle is specialized in consuming H. haydeniana. P. laevissimus also lives in California, Oregon, and Washington and feeds on millipedes like H. haydeniana. (Denton 1997).

Figure 1. Raccoons are one of the many diverse organisms that may feed on millipedes.

Not all H. haydeniana interactions are negative, however, some inter-organismal relationships are quite beneficial. For example, Trichomycetes are obligatory symbiotrophic fungi that live in the intestines of millipedes. The fungi’s mycelia help break down the dead plant material while the millipede’s hindgut provides a habitat for the fungi. (Sierwald & Bond 2007).

Interactions References in Order of Appearance:

Sierwald, P. and Bond, J.E. 2007. Current status of the myriapod class diplopoda (millipedes): taxonomic diversity and phylogeny. The Annual Review of Entomology.  <URL: http://www.annualreviews.org/doi/pdf/10.1146/annurev.ento.52.111805.090210> Accessed 19 November 2013. 

Denton, M. 1997. Promecognathus laevissimus dejean 1829. The Evergreen State College. <URL: http://academic.evergreen.edu/projects/evergreenBiota/kingdom/animalia/phylum/arthropoda/class/insecta/order/coleoptera/family/
carabidae/GENERA/PROMECOGNATHUS/P_laevissimus.HTM > Accessed 9 November 2013.

Interactions Photo Reference:

Wikimedia Commons 2009. < http://commons.wikimedia.org/wiki/File:Raccoon_(4152678243).jpg> Accessed 5 December 2013.

Adaptations  References in Order of Appearance:

Eisner, T., H.E. Eisner, J.J. Hurst, F.C. Kafatos, and J. Meinwald. 1963. Cyanogenic glandular apparatus of a millipede. Science 139: 1218-1220

Rockstein, M. 1978. Biochemistry of Insects. Academic Press, New York, New York, USA.

 Eisner, T. and J. Meinwald. 1966. Defensive Secretions of Arthropods. Science 153

Hudson, B.J. and G.A. Parsons. 1997. Giant millipede “burns” and the eye. Trans R Soc Trop Med Hyg 91: 183-185

Adaptations Photo References in Order of Appearance:

Wikimedia Commons 2006.<http://commons.wikimedia.org/wiki/File:Millipede_toes_toxin_diplopoda.png> Accessed 6 December 2013.