Polypedilum vanderplanki
{{Short description|Species of fly}}
{{Speciesbox
| taxon = Polypedilum vanderplanki
| authority = Hinton, 1951
}}
Polypedilum vanderplanki or the sleeping chironomid, is a dipteran in the family Chironomidae (non-biting midges). It occurs in the semi-arid regions of the African continent (e.g. northern Nigeria and Uganda). Its larvae are found in small tubular nests in the mud at the bottom of temporary pools that frequently dry out during the lifetime of P. vanderplanki larvae. Under these conditions, the larvae's body desiccates to as low as 3% water content by weight. In the dehydrated state the larvae become impervious to many extreme environmental conditions, and can survive temperatures from 3 K to up to 375 K, very high (7000 gray) levels of gamma-rays, and exposure to vacuum.{{cite journal| title=Polypedilum vanderplanki: an anhydrobiotic insect as a potential tool for space biology| bibcode=2006cosp...36.2237O|author1=Okuda, T. |author2=Watanabe, M. |author3=Sychev, V. |author4=Novikova, N. |author5=Gusev, O. |author6=Saigusa, M. |journal=36th COSPAR Scientific Assembly in Beijing | date=Jul 2006| volume=36| page=2237}}{{cite journal| doi=10.1038/188336a0| journal=Nature |year=1960|title=A fly larva that tolerates dehydration and temperatures of -270°C to +102°C|author=Hinton HE| volume=188| issue=4747|pages=336–337|bibcode = 1960Natur.188..336H | s2cid=4260914 }} It is one of few metazoans that can withstand near complete desiccation (anhydrobiosis) in order to survive adverse environmental conditions. Slow desiccation (0.22 ml per day) enabled larvae to synthesize 38 μg trehalose/individual, and all of them recovered after rehydration, whereas larvae that were dehydrated 3 times faster accumulated only 6.8 μg trehalose/individual and none of them revived after rehydration.{{cite journal | doi= 10.1093/icb/45.5.710 | title= Factors Inducing Successful Anhydrobiosis in the African Chironomid Polypedilum vanderplanki: Significance of the Larval Tubular Nest | year=2005 | author=Kikawada, Takahiro | journal=Integrative and Comparative Biology | volume=45 | issue= 5 | pages= 710–714| pmid= 21676821 |display-authors=etal| doi-access=free }}{{cite journal | doi=10.1073/pnas.0706197105 | journal=PNAS |title=Vitrification is essential for anhydrobiosis in an African chironomid, Polypedilum vanderplanki| year= 2008 | volume= 105 | issue=13 | pages=5093–5098| pmid= 18362351 | pmc=2278217|bibcode = 2008PNAS..105.5093S | last1=Sakurai | first1=M | last2=Furuki | first2=T | last3=Akao | first3=K | last4=Tanaka | first4=D | last5=Nakahara | first5=Y | last6=Kikawada | first6=T | last7=Watanabe | first7=M | last8=Okuda | first8=T | doi-access=free }} Late Embryo Abundant (LEA), anti-oxidant, and heat-shock proteins may also be involved in survival.{{cite web | url=http://www.nias.affrc.go.jp/anhydrobiosis/Sleeping%20Chironimid/e-taisei.html | title=Sleeping Chironmid. Study of tolerance|date=2011|publisher=Sleeping Chironomid Research Group, National Institute of Agrobiological Sciences, Japan}}{{cite journal | doi=10.1371/journal.pone.0014008 | journal=PLoS ONE| year=2010 | volume= 5 | issue=11 | pages=e14008 | title=Anhydrobiosis-Associated Nuclear DNA Damage and Repair in the Sleeping Chironomid: Linkage with Radioresistance | editor1-first=Zhongjun | editor1-last=Zhou | author= Gusev, Oleg | pmid=21103355 | pmc=2982815|bibcode = 2010PLoSO...514008G |display-authors=etal| doi-access=free}}{{cite journal | doi= 10.1007/s12192-010-0223-9 | journal=Cell Stress and Chaperones | year=2011 | volume=16 | issue= 1|pages=81–90|pmid= 20809134 |title=Expression of heat shock protein-coding genes associated with anhydrobiosis in an African chironomid Polypedilum vanderplanki | pmc=3024092| last1=Gusev | first1=O | last2=Cornette | first2=R | last3=Kikawada | first3=T | last4=Okuda | first4=T }} This species is considered the most cold-tolerant insect species, able to survive liquid helium (−270 °C) exposure for up to 5 min. with a 100% survival rate when desiccated to 8% water content.{{cite book | url=http://entnemdept.ufl.edu/walker/ufbir/chapters/chapter_04.shtml | title=Book of Insect Records|chapter=Chapter 4: Most Tolerant of Cold|editor=Walker, Thomas J. |date=1994|author=Hall, Jason P.W. |publisher=University of Florida|oclc=439076927 }}