It is fairly common to spot colored insects with iridescent effect where their surfaces show a change in color when viewed from different angles. Some insects use this for camouflage while others use it to become more attractive.
But when a normally brown or gray-colored insect appears blue, an underlying health condition might be present. This was recently observed by photographer Josh Coogler from Dallas, North Carolina, where the woodlice from his backyard show unusual blue discoloration, as reported in Newsweek. It was found out to be a result of infection from invertebrate iridescent viruses (IIVs), also known as iridovirus. Scientists are studying how this phenomenon can be used in determining the effectiveness of antiviral substances.
Effects and Transmission of Iridovirus in Invertebrates
Invertebrate iridescent viruses (IIVs) belong to a family of large viruses with double-stranded DNA. They have been reported from both invertebrate and vertebrate animals, but they were first discovered in terrestrial isopods in 1980. According to a study conducted at Instituto de Ecología, out of the 108 identified invertebrate species affected by IIVs, 95% are arthropods which are mainly insects and terrestrial arthropods.
Infected invertebrates show violet, blue, or turquoise iridescence in their shells. This distinctive color is a result of the formation of crystal in the tissue of the host animal. The crystals get accumulated in their external skeleton and causes a change in color from gray or brown to blue or violet. Aside from the change in color, some infections are observed that do not seem to be deadly. However, the effect of iridovirus was found to be lethal for insects in their larval or pupal stages.
IIVs mostly infect invertebrates that live in damp and aquatic habitats due to their high sensitivity to dry environments. The decreased activity from dehydration is attributed to their viral structure that allows them to be highly stable in water. As isopods prefer moist habitats, it makes them an ideal host for the IIVs.
A study published by ScienceDirect confirms that the virus is transmitted through cannibalism or consumption of infected host. It is also assumed that this mode can pave the way to vertical viral transmission from the parent host to its offspring. On the other hand, studies have shown that iridoviruses do not pose threats to humans. Even if we get in contact with infected isopods, we are also not at risk of catching this virus.
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Potential Benefit to Drug Development
This phenomenon is not expected to cause panic as it is found to be harmless to humans. In fact, it can open the way to understanding the nature of antiviral substances.
A team of researchers led by Dr. Samuel T. Jones, materials and antiviral expert from the University of Manchester, aims to create a revolutionary antiviral material that can be used in destroying viruses on contact. If found successful, this breakthrough can be used as treatment in fighting pandemic diseases, according to Dr. Jones.
To measure the effectiveness of this material, Dr. Jones proposed a virus tester using woodlouse that has been infected by IIVs. A quick colorimetric test will be done to woodlice to check if the antiviral material is effective or not.
As part of this project, a campaign has been launched by Dr. Jones' team where they ask help from the general public in finding these blue woodlice. Volunteers can send their collected woodlice to the University of Manchester to be studied for research purposes.
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