# Is a fly clean when he emerges from his pupa? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [August 22, 2022, 7:30pm UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105 "2022-08-22T19:30:19Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [August 22, 2022, 7:30pm UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/1 "2022-08-22T19:30:19Z")
Does a fly pick up most of his bacteria from things he lands on? Or is it a carryover from his maggot days? ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [August 22, 2022, 9:09pm UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/2 "2022-08-22T21:09:15Z")
IANAE\* but I would imagine most flies go through their entire life cycle without picking up any harmful bacteria at all. Lifecycles are too short. I would also guess that bacteria picked up _in pupae_ (if that is the correct term) would harm the fly. So, in my inexpert opinion, I think adult flies pick up their bacteria as they go about their short-lived daily business. \* I Am Not An Etymologist ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [August 23, 2022, 1:24am UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/3 "2022-08-23T01:24:47Z")
> [@HoneyBadgerDC](#): > > Does a fly pick up most of his bacteria from things he lands on? Or is it a carryover from his maggot days? Adult flies like spoiled food as much as maggots do. I doubt bacteria from whatever the maggot feasted on plays much of a role in a fly’s “vectoring” beyond the first couple of days after leaving the pupae. Admittedly that is a significant fraction of a fly’s life. > **[Fruit Flies as Potential Vectors of Foodborne Illness - PubMed](https://pubmed.ncbi.nlm.nih.gov/29474149/)** > > Fruit flies are a familiar sight in many food service facilities. Although they have been long considered as "nuisance pests," some of their typical daily activities suggest they may pose a potential public health threat. The aim of this study was to... ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [August 23, 2022, 2:21am UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/4 "2022-08-23T02:21:11Z")
> [@scudsucker](#): > > - I Am Not An Etymologist Or even an Entomologist? 😄 Both of them, of course, know [how to tell the difference between a clover and a plover.](https://books.google.com/books?id=grpBAAAAIAAJ) > [@](#): > > The Plover and the Clover can be told apart with ease, > By paying close attention to the habits of the Bees; > For Entomologists aver, the Bee can be in Clover, > While Etymologists concur, there is no B in Plover. ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [August 23, 2022, 2:58am UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/5 "2022-08-23T02:58:53Z")
Oops! Maggots in my brain, I suppose. ---
**Author:** ![Latimera](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/latimera/32/497_2.png) [@Latimera](https://boards.straightdope.com/u/Latimera)\ **Post date:** [August 23, 2022, 3:19am UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/6 "2022-08-23T03:19:28Z")
There are more than 150,000 species in the the order Diptera (flies). So it would very much depend on what species of fly you were referring to. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 23, 2022, 12:29pm UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/7 "2022-08-23T12:29:53Z")
> [@scudsucker](#): > > IANAE\* but I would imagine most flies go through their entire life cycle without picking up any harmful bacteria at all. Lifecycles are too short. ‘Harmful’ in terms of bacteria is pretty much like ‘weed’ in terms of gardening. Flies have a microbiome - gut bacteria and such - those bacteria can be harmful to humans, for example if they get into the top end of our digestive system in significant population, or take hold in a wound, but that’s also true of the bacteria of our very own microbiome. ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [August 25, 2022, 10:59pm UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/8 "2022-08-25T22:59:44Z")
Black soldier flies are considered “clean” and the larvae feed on decaying food waste. These are the ones you want to see in your compost bin. They don’t show any interest in feces or like some house flies, or much interest in your current meal. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [August 26, 2022, 12:37am UTC](https://boards.straightdope.com/t/is-a-fly-clean-when-he-emerges-from-his-pupa/970105/9 "2022-08-26T00:37:07Z")
> [@thelurkinghorror](#): > > soldier flies are considered “clean” and the larvae feed on decaying food waste. These are the ones you want to see in your compost bin. They don’t show any interest in feces or like some house flies, or much interest in your current meal I have been looking into soldier flies larva as a stuffing for sausage that could be fed to pets