{{Short description|Species of beetle}} {{redirect|King worm|the episode of ''Adventure Time''|King Worm}} {{Redirect|Superworm|the 2022 animated short film|Superworm (film)}} {{Speciesbox | image = Zophobas morio.jpg | genus = Zophobas | species = atratus | authority = (Fabricius, 1775) | synonyms = {{species list |Helops morio |Fabricius, 1777 |Tenebrio atratus |Fabricius, 1775 |Zophobas morio |(Fabricius, 1776) |Zophobas rugipes |Kirsch, 1886 }} | synonyms_ref = <ref name=GBIF>{{GBIF |title=''Zophobas atratus'' (Fabricius, 1775) |id=7882289 |access-date=18 April 2026}}</ref> }}
'''''Zophobas atratus''''' is a species of darkling beetle, whose larvae are known by the common name '''superworm''', '''kingworm''', '''barley worm''', and '''morio worm'''. Superworms are common in the reptile pet industry as food, along with giant mealworms (''Tenebrio molitor'' larvae treated with juvenile hormone<ref>{{Cite web |url=https://brill.com/view/journals/jiff/10/9/article-p1633_11.xml?rskey=wRL9AZ&result=1 |access-date=2026-03-29 |website=brill.com}}</ref>).
The larvae resemble very large mealworms, about 50 to 60 mm (1.7–2.25 in) long when full size, but unlike mealworms, the ends of their bodies are very dark, almost black. Once they reach sufficient maturity, the larvae go stiff and still in a "C" shape to pupate. They emerge 1-3 weeks later with a white to light brown colour; eventually darkening to black. Pupation is commonly delayed by keeping larvae in high density with other larvae and plentiful food, and can be resumed by isolating larvae for 7–10 days. They will then pupate and, upon maturation, emerge as darkling beetles.<ref>{{cite journal |title=The Superworm, ''Zophobas morio'' (Coleoptera:Tenebrionidae): A 'Sleeping Giant' in Nutrient Sources |journal=Journal of Insect Science |date=2021-04-09 |last1=Rumbos |first1=C. I. |last2=Athanassiou |first2=C. G. |volume=21 |issue=2 |doi=10.1093/jisesa/ieab014 |pmid=33834209 |pmc=8033247 |url=https://academic.oup.com/jinsectscience/article/21/2/13/6218202 |access-date=2021-05-23 |doi-access=free }}</ref>
''Zophobas atratus'' is generally accepted by captive lizards, turtles, frogs, salamanders, birds, koi and other insectivorous animals. Their nutritional values are similar to those of mealworms, so it is possible that supplementation with calcium is necessary if they are used as a staple food item. In some cases they are preferred over mealworms due to their softer exoskeleton,<ref>[https://wormmy.com/mealworms-vs-superworms/ Mealworms vs. Superworms (the difference?) - answered. Wormmy.] (2022, August 12). Retrieved 2023-03-21.</ref> making them more digestible to some reptiles. The larvae are odor-free, but the adult beetles possess a pungent chemical defense that may be released when provoked. ''Zophobas atratus'' can easily be contained, making them ideal for breeding to feed a collection of captive insectivores. The nutritional profile of the larvae is "46.80% proteins, 43.64% lipids, 8.17% ashes and 1.39% carbohydrates."<ref>{{cite journal |last1=Soares Araújo |first1=Rafael Ribeiro |last2=dos Santos Benfica |first2=Tatiana Aparecida Ribeiro |last3=Ferraz |first3=Vany Perpetua |last4=Moreira Santos |first4=Eleonice |title=Nutritional composition of insects ''Gryllus assimilis'' and ''Zophobas morio'': Potential foods harvested in Brazil |journal=Journal of Food Composition and Analysis |date=March 2019 |volume=76 |pages=22–26 |doi=10.1016/j.jfca.2018.11.005 |s2cid=104437154 }}</ref>
==Distribution== This beetle occurs naturally in tropical regions of Central and South America,<ref>{{cite journal |last1=Bousquet |first1=Yves |last2=Thomas |first2=Donald B. |last3=Bouchard |first3=Patrice |last4=Smith |first4=Aaron D. |last5=Aalbu |first5=Rolf L. |last6=Johnston |first6=M. Andrew |last7=Steiner Jr. |first7=Warren E. |date=2018 |title=Catalogue of Tenebrionidae (Coleoptera) of North America |journal=ZooKeys |issue=728 |pages=1–455 |doi=10.3897/zookeys.728.20602 |doi-access=free |pmid=29416389 |bibcode=2018ZooK..728....1B |url=https://zookeys.pensoft.net/article/20602/download/pdf/287681 |pmc=5799738 }}</ref> but has spread across the world for use as food for reptiles and other insectivorous pets.{{citation needed|date=August 2024}}
==Taxonomy== The name ''Zophobas morio'' is still very widely in use in the scientific literature, although it has been synonymised with ''Z. atratus''.<ref name="Marcuzzi-1971">{{cite journal |last1=Marcuzzi |first1=G. |last2=d'Aguilar |first2=J. |date=1971 |title=Catalogue raisonné des insectes des Antilles françaises. 3. Coléoptères: Tenebrionidae |journal=Annales de Zoologie, Écologie Animale |volume=3 |pages=79–96 }}</ref> Since ''Z. morio'' was published later (in the year 1777) than ''Z. atratus'' (published in 1775), the former name is a junior subjective synonym of the latter, and ''Z. atratus'' is the valid name of this species.
==Relationship with humans==
===As pet feed=== As with the popular mealworm, ''Z. atratus'' larvae (commonly known as superworms, and under the name ''Zophobas morio'') are widely used in pet care, more specifically as feed.
Superworms are relatively high in protein and fat, which make them attractive pet feed for captive reptiles, amphibians, fish, and birds, and other types of insectivores like ants. Their ability to stay alive without eating for 1–2 weeks makes the keeping process highly feasible for bulk commercial availability around the world. However, pet owners are advised to keep them in warm temperatures as, unlike the mealworm, superworms do not enter the process of hibernation. They are also known to bite and agitate when threatened by handling, although the bite is not very painful.
===As waste disposal agents=== Larvae of ''Zophobas atratus'', ''Tenebrio molitor'' and ''Tenebrio obscurus'' all have been found to consume expanded polystyrene foam; they are examples of plastivores.<ref name="Yang">{{cite journal |last1=Yang |first1=Li |last2=Gao |first2=Jie |last3=Liu |first3=Ying |last4=Zhuang |first4=Guoqiang |last5=Peng |first5=Xiawei |last6=Wu |first6=Wei-Min |last7=Zhuang |first7=Xuliang |title=Biodegradation of expanded polystyrene and low-density polyethylene foams in larvae of ''Tenebrio molitor'' Linnaeus (Coleoptera: Tenebrionidae): Broad versus limited extent depolymerization and microbe-dependence versus independence |journal=Chemosphere |date=1 January 2021 |volume=262 |article-number=127818 |doi=10.1016/j.chemosphere.2020.127818 |pmid=32771707 |bibcode=2021Chmsp.26227818Y |s2cid=224882094 |url=https://www.sciencedirect.com/science/article/abs/pii/S0045653520320130 |issn=0045-6535|url-access=subscription }}</ref> ''Zophobas atratus'' breaks down polystyrene through a two-stage process: first by mechanically shredding the plastic into smaller pieces through chewing, which exposes pieces to oxygen atoms, and then by using bacterial gut enzymes to depolymerize the pieces.<ref name="Ong">{{cite journal |last1=Ong |first1=Sandy |title=The living things that feast on plastic |journal=Knowable Magazine |date=24 August 2023 |doi=10.1146/knowable-082423-1|doi-access=free |url=https://knowablemagazine.org/article/food-environment/2023/how-to-recycle-plastic-with-enzymes|url-access=subscription }}</ref><ref name="Sun">{{cite journal |last1=Sun |first1=J |last2=Prabhu |first2=A |last3=Aroney |first3=STN |last4=Rinke |first4=C |title=Insights into plastic biodegradation: community composition and functional capabilities of the superworm (''Zophobas morio'') microbiome in styrofoam feeding trials |journal=Microbial Genomics |date=June 2022 |volume=8 |issue=6 |doi=10.1099/mgen.0.000842 |doi-access=free |pmid=35678705 |pmc=9455710 }}</ref> ''Zophobas atratus'' larvae fed with a polystyrene diet were more active and managed to gain a slight amount of weight compared to the same type of larvae on a starvation diet.<ref name="Samuels">{{cite news |last1=Samuels |first1=Fionna |title='Superworms' Eat—and Survive on—Polystyrene |url=https://www.scientificamerican.com/article/superworms-eat-and-survive-on-polystyrene/ |work=Scientific American |date=June 9, 2022 |language=en}}</ref><ref name="Kilvert">{{cite news | url=https://www.abc.net.au/news/science/2022-06-10/superworm-eats-polystyrene-has-recycling-potential/101128630 | author-first=Nick |author-last=Kilvert |title='Superworms' survive solely on polystyrene, as researchers look to create plastic recycling technology | newspaper=ABC Science | date=9 June 2022 }}</ref>
==See also== *Entomophagy
==Gallery== <gallery mode="packed"> File:Zophobas morio larva - top (aka).jpg|''Larva'' File:Pupa of the superworm darkling beetle (Zophobas atratus).jpg|''Newly formed pupa'' File:Moriopop.jpg|''Pupa close to eclosion'' File:Zophobas-morio-7005.jpg|''Young male beetle'' File:Zophobas morio adultsmall.jpg|''Female pinned adult specimen'' </gallery>
==References== {{Reflist}}
==Further reading== {{Wikispecies|Zophobas morio}} {{commons category|Zophobas morio}} {{refbegin}} *{{cite journal |last1=Freye |first1=Henry B. |last2=Esch |first2=Robert E. |last3=Litwin |first3=Catherine M. |last4=Sorkin |first4=Louis |title=Anaphylaxis to the Ingestion and Inhalation of ''Tenebrio molitor'' (Mealworm) and ''Zophobas morio'' (Superworm) |journal=Allergy and Asthma Proceedings |date=1 July 1996 |volume=17 |issue=4 |pages=215–9 |pmid=8871741 |doi=10.2500/108854196778996903 }} *{{cite journal |last1=Leung |first1=Dong |last2=Yang |first2=Depo |last3=Li |first3=Zhuoxue |last4=Zhao |first4=Zhimin |last5=Chen |first5=Jianping |last6=Zhu |first6=Longping |title=Biodiesel from ''Zophobas morio'' Larva Oil: Process Optimization and FAME Characterization |journal=Industrial & Engineering Chemistry Research |date=5 January 2012 |volume=51 |issue=2 |pages=1036–1040 |doi=10.1021/ie201403r }} *{{cite journal |last1=Prado |first1=R. A. |last2=Santos |first2=C. R. |last3=Kato |first3=D. I. |last4=Murakami |first4=M. T. |last5=Viviani |first5=V. R. |title=The dark and bright sides of an enzyme: a three dimensional structure of the N-terminal domain of ''Zophobas morio'' luciferase-like enzyme, inferences on the biological function and origin of oxygenase/luciferase activity |journal=Photochemical & Photobiological Sciences |date=2016 |volume=15 |issue=5 |pages=654–665 |doi=10.1039/C6PP00017G |pmid=27101527 |bibcode=2016PhPhS..15..654P |s2cid=206050300 }} *{{cite journal |last1=Latney |first1=La'Toya V. |last2=Toddes |first2=Barbara D. |last3=Wyre |first3=Nicole R. |last4=Brown |first4=Dorothy C. |last5=Michel |first5=Kathryn E. |last6=Briscoe |first6=Johanna A. |title=Effects of various diets on the calcium and phosphorus composition of mealworms (''Tenebrio molitor'' larvae) and superworms (''Zophobas morio'' larvae) |journal=American Journal of Veterinary Research |date=February 2017 |volume=78 |issue=2 |pages=178–185 |doi=10.2460/ajvr.78.2.178 |pmid=28140633 }} {{refend}}
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Category:Tenebrioninae Category:Beetles described in 1776 Category:Pet foods Category:Insects as feed Category:Plastivores