#bioPGH Blog: Mosquitoes
Jul 25
2019

#bioPGH Blog: Mosquitoes

By Dr. Maria Wheeler-Dubas, Research and Science Education Outreach Manager

Biophilia NetworkA resource of Biophilia: Pittsburgh, #bioPGH is a weekly blog and social media series that aims to encourage both children and adults to reconnect with nature and enjoy what each of our distinctive seasons has to offer. 

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I will warn you now— this will be an itchy read! Even as I type, I am giving a less-than-loving glance at angry red spots on my ankles, the remnants of those classic summer accompaniments: mosquitoes. Mosquitoes are members of the true fly family Diptera along with houseflies, crane flies and gnats. Pennsylvania is home to approximately 60 species of mosquitoes, but if you’re like me, you may have wondered, why do we even have these unwelcome little fiends? Do they play an important ecological role, or just make us itch? To answer that question, let’s dig a little into some mosquito biology, shall we?

Many of us have heard this before, but only female mosquitoes bite — the males actually don’t even have the mouth parts needed to suck blood — and that bite is an important part of mosquito reproduction. The females use the protein from their blood meals as source of nourishment to lay eggs. To bite their hosts, mosquitoes actually use six ultra-thin “needles” called stylets that break the skin, and each of those little stylets has a job. Two of those stylets have serrated “teeth” to help cut their way in, another set of stylets helps to hold the newly broken skin open, and another stylet injects anti-coagulants to keep our blood flowing while a final stylet breaks into a blood vessel and sucks up the coveted blood meal itself.

The PBS video below gives a close-up itchy look at how that bite works!

 

In case you were wondering where the nourishment from your blood is going, a female will eventually lay her eggs in an aquatic environment like a pond or shallow water-filled depression or ditch, but they can also be laid in anything that collects water, like discarded tires, buckets, birdbaths, etc. A few species may not necessarily lay their eggs directly in water, but they will at least seek out damp surfaces near water. (Terrifying fun fact: the eggs of one of these species, Aedes aegypti, can survive being dry for up to 72 hours!) For the majority of mosquito species, after the eggs hatch into larvae, they will remain in an aquatic environment until they reach their adult stage, which could be 2 – 4 weeks depending on the species.

Back to our question, though: does the environment really need mosquitoes? What purpose do they serve? If they were wiped out by some mosquito epidemic, would there really be any harm to our wild communities? That question has been floated more and more recently, but the answer to is complex. For starters, there are indeed animals who absolutely depend on mosquitoes as prey. Many fish and bird species actually specialize on mosquitoes in either their adult and aquatic larval stages, and the loss of mosquitoes would be devastating to them. To play devil’s advocate, could those animals just eat something else? Yes, but shifting the target prey to another insect species could cause cascading series of problems within food webs. What if that caused a change in pollinator density and resulted in a decrease in the reproduction of important food crops or wild vegetation? And there are some mosquito species that serve as pollinators themselves—particularly the males, who never take a blood meal.

The major concern, though, it that mosquito-borne disease is globally a major hazard. Malaria alone impacts 250 – 500 million people per year, not to mention dengue, Zika, West Nile, lymphatic filariasis, yellow fever, Japanese encephalitis and others. From a human standpoint, mosquitoes are indeed troublesome, and as climate changes continue to strengthen their disease impact, the future of mosquito management will be increasingly important! We may not completely understand their role in the environment, but we can certainly support research that is looking for ways to stop disease transmission—even research right here in Pittsburgh!

Connecting to the Outdoors Tip: To keep mosquito numbers low, be sure there is no stagnant, standing water around for mosquitoes to lay their eggs. Cups, old tires, buckets and other discarded items can all become mosquito habitat, so by properly disposing of trash, we can keep our home looking clean while avoiding getting eaten every time we go outdoors.

Continue the Conversation: Share your nature discoveries with our community by posting to Twitter and Instagram with hashtag #bioPGH, and R.S.V.P. to attend our next Biophilia: Pittsburgh meeting.

Resources

Mosquitoes of Pennsylvania – PA DEP and Grove City College 

Nature – Ecology: A World Without Mosquitoes

Photo Credits: Cover, Katja Schulz, CC-BY-2.0


Comments

Why do mosquitos bite some people and not others? I’m always the victima

By Caryn on Jul 26, 2019

Hi Caryn! Mosquitoes do indeed seem to target some folks more than others (they love me!), and it seems that chemistry plays a role in that. Blood type, carbon dioxide, and just unique gene expression all seems to play a role.

https://www.scientificamerican.com/article/do-mosquitoes-bite-some-people-more-than-others/

By Maria Wheeler-Dubas on Jul 30, 2019

Thank you for the blog entry on mosquitoes.  I appreciate learning the variety of roles played by mosquitoes in different environments and food systems, e.g. plant pollinator and source of food for fish, birds and bats.  The disease spreading capacity of mosquitoes can be devastating and is more widely discussed scientific articles and the media..  I value learning a larger picture of the impact of mosquitoes worldwide.  Mosquitoes pollinate cocoa plants, contributing to chocolate production.  Who knew?  I especially appreciate the link to the Nature article that provides more details and debate about the impact of eradicating mosquito species.

By Kimberly on Aug 1, 2019