Arachnocampa luminosa
Arachnocampa luminosa | |
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Glowworm (Arachnocampa luminosa) and silk snares | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Diptera |
Family: | Keroplatidae |
Genus: | Arachnocampa |
Species: | A. luminosa
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Binomial name | |
Arachnocampa luminosa (Skuse, 1891)
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Synonyms | |
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Arachnocampa luminosa (Skuse, 1891), commonly known as New Zealand glowworm or simply glowworm, is a species of
The first written record of the species dates from 1871 when it was collected from a
Distribution
Arachnocampa luminosa is widespread in both the North and the South Island of New Zealand although populations generally occur in cave systems and in native bush where prey species are available and humidity is high. Some sites have become popular destinations for tourists wanting to see the glowworms. These include the caves in Waitomo, Waipu, Inglewood and Te Ana-au,[2][5] and also in areas of native vegetation such as the Wellington Botanical Gardens.[6]
Life cycle
The spherical eggs (0.75mm in diameter) are usually deposited directly onto the cave wall. Upon hatching, the cylindrical larva immediately begins to glow. When they first emerge they are usually between 3 and 5 millimeters long, and will grow to between 30 and 40mm across several months. The larva may move around on the surface of the cave or bank before selecting a site to begin producing its silk nest.[2] Most larvae emerge during the spring.[7]
The larva spins a nest out of silk on the ceiling of the cave and then hangs down up to 30 silk threads along which it regularly places small sticky droplets.
After five larval instars,[7] the larva will suspend itself on a long thread and pupates over up to 24 hours. The pupal phase lasts about two weeks. During this time, the pupa continue to glow although males eventually lose their glow. The adults which eventually emerge are poor fliers.[2] Adults usually emerge during the winter and tend to live for up to 76 hours in the case of females and up to 96 hours in the case of males.[7] Females usually lay over 100 eggs and eggs usually hatch after about 20 days.[2]
Sources of mortality for glowworms include predation by cave
Behavior and Ecology
This luminescent species resides in dark, cool and damp places such as caves and their diet is predatory, they use their bluish green glow to lure in their prey.[8] Compared to other caves the Temperature and Humidity inside the Glowworm Cave are atypical. When comparing climatic data from 1977–80 and 1955 it is shown that the cave was more stable in 1955 than it is now, this increase in climatic variability is thought to be due to the fact that in 1975 the entrance was unblocked forcing the cave to behave as a wind tunnel.[7]
The behavior observed of both the pupae and adult New Zealand glowworm has shown that the longest stage that the Arachnocampa goes through is its larval stage which can last up to a year. Females of A. luminosa are the ones that are actually luminescent but it is still unknown whether or not the female's light is what attracts a male opposed to pheromones, especially when it could possibly be both. Their eyes are designed to function well with the spectral range that covers UV to green wavelengths. Adult A. luminosa are not very good fliers and they only live for a few days, on top of that they do not feed either.[10]
Bioluminescence
The larvae of this species glow to attract prey into their threads.
The pupae and adults of this species also produce light although the purpose is not clear. One suggestion has been that the light allows adult males to find potential mates.
References
- ^ Gatenby, J. Bronte (May 1960). "The New Zealand Glow-Worm". Tuatara: Journal of the Biological Society. 8 (2): 86–92. Retrieved 27 July 2015.
- ^ a b c d e f Richards, A. M. (1960). "Observations on the New Zealand Glow-worm "Arachnocampa luminosa" (Skuse) 1890". Transactions of the Royal Society of New Zealand. 88: 559–574.
- ^ Meyrick, E. (1886). "A luminous insect larva in New Zealand". The Entomologist's Monthly Magazine. 22: 266–267.
- ISSN 0370-047X.
- ^ "7 Places to See the Famous Glowworms in New Zealand". Backpacker Guide NZ. 2019.
- ^ "Attractions". Wellington city Council. 2019.
- ^ ISSN 0303-6758.
- ^ ISSN 1077-8306.
- .
- PMID 17285566.
- OCLC 767691334.
- ^ PMID 29459729.
- PMID 494236.
- OCLC 154319848.
- S2CID 86160354.
- OCLC 847201220.
Further reading
- The Glow-Worm, Ormiston Walker and Judy Kerdel, MacMillan New Zealand, 1990, ISBN 0-7329-0121-9. (A children's book.)
- Glowworm article, Encyclopædia Britannica, 15th edition
- Broadley, R. A. and Stringer, I.A.N. (2009) Larval behaviour of the New Zealand glowworm, Arachnocampa luminosa (Diptera: Keroplatidae), in bush and caves. In: V.B. Meyer-Rochow (Ed.), Bioluminescence in Focus - A Collection of Illuminating Essays (pp. 325–355). Research Signpost. Kerala.
External links
Media related to Arachnocampa luminosa at Wikimedia Commons
- Arachnocampa luminosa discussed on RNZ Critter of the Week, 20 July 2018
- Soil Bugs - An illustrated guide to the New Zealand invertebrates
- Glowworm article in the Encyclopaedia of New Zealand 1966
- Glowworms page (Archived 2009-10-25)