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STRAITS POND MIDGES: Biology, Ecology, and Problem Populations

STRAITS POND MIDGES: Biology, Ecology, and Problem Populations. Straits Pond inhabitants:. Anadromous/Catadromous/ Amphidromous fish Migratory shorebirds and waterfowl Invasive plants and animals Ailanthus altissima Phragmites australis Swans. Three-Spined Stickleback. Invasive plants ….

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STRAITS POND MIDGES: Biology, Ecology, and Problem Populations

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  1. STRAITS POND MIDGES:Biology, Ecology, and Problem Populations

  2. Straits Pond inhabitants: • Anadromous/Catadromous/ Amphidromous fish • Migratory shorebirds and waterfowl • Invasive plants and animals • Ailanthus altissima • Phragmites australis • Swans Three-Spined Stickleback

  3. Invasive plants … Tree of HeavenAilanthus altissima

  4. Invasive species …

  5. Straits Pond invertebrates: • Aquatic beetles • Dragon/Damselflies • Familiar Bluet • Big Bluet ? • Seaside Dragonlet • Needham’s Skimmer ? • Periwinkle Littorina sp. • Green Crab C. meanus Uvarus sp. COLEOPTERA: DYTISCIDAE

  6. Skimmer Dragonfly Larva ODONATA: LIBELLULIDAE

  7. Flies (Diptera) No-see-ums (Ceratopogonidae) Greenheads (Tabanidae) Craneflies (Tipulidae) Midges (Chironomidae) Straits Pond invertebrates:

  8. MIDGES • Abundant and ubiquitous • Inhabit all aquatic habitats • Adults do not bite • Significant food source for many other species • Pollution-tolerant

  9. Midge Taxonomy • Insect order Diptera, or “True Flies” • Family Chironomidae • 20,000+ species • >350 sub-families • >2,000 spp in N.A.

  10. Aquatic dipteran larvae Merritt & Cummins, 1996 Aquatic Insects of N. America

  11. GENUS:Chironomus C. decorus C. riparius C. plumosus C. dorsalis >20 spp. in N.A. • Multivoltine - produce 1 to 4 generations each year • Larvae are detritivores • Larvae burrow, build U-shaped tubes • Protection • Respiration • Body fluids contain high-affinity hemoglobin

  12. Chironomus life cycle • Eggs hatch within 3 days • Larvae live 5 - 50 days • Temperature • Food availability • Depth preferences • Overwinter in bottom sediments in mid-larval stages

  13. Chironomus larval ecology • Associated with soft upper sediment layers • Densities correlated with organic content • Consume bacterial and fungal components • Lower densities found in gravel (ponds) • Relatively drought and freeze tolerant • Do not migrate during dry/cold spells

  14. Pupal stage www.first-nature.com • Brief - 2 to 5 days • Remain in larval tube • Float to surface before emergence

  15. Pupal stage Merritt & Cummins, 1996 Aquatic Insects of N. America

  16. Adult stage www.first-nature.com • Adults live a few days to weeks • Feed on nectar, or do not feed • Females produce one batch of eggs

  17. Adult stage Merritt & Cummins, 1996 Aquatic Insects of N. America

  18. Super Floss Chironomid Courtesy of Washington Fly Fishing Gallery www.washingtonflyfishing.com

  19. Factors contributing toproblem populations: • Stagnation • Warmer temperatures • Lower Dissolved Oxygen concentration • Nutrient loading • Septic systems and fertilizers … N, P, K • Decayed algae and plants … C

  20. Annoying swarms gather in backyards Adult midges are attracted to lights Food is abundant Larvae thrive in harsh environments Beware of “bug-zappers” Attract more insects Kill beneficial spp. Use yellow bulbs Reduce nutrient sources Lawns/Septic systems Decaying plant material Circulate/aerate water Problems & Suggestions

  21. Alternative control methods • Manual removal of detritus • Bacterial breakdown of organic sediments

  22. Alternative control methods • Wind or solar powered water aeration • Introduce predators • Dragonfly larvae? • Bream

  23. Estimated percentages of aquatic invertebrate taxa Figure 1. Freshwater streams

  24. Estimated percentages of aquatic invertebrate taxa Figure 2. Tidal ponds

  25. Midge Predators • Fish • Feed on aquatic stages • Most effective predators • Waterfowl • Feed on aquatic stages

  26. Midge Predators • Dragons and Damsels • Consume all stages • Charismatic • Diving Beetles • Voracious consumers of aquatic stages • Tolerant, prolific • Microorganisms • Fungi, Bti

  27. Seaside Dragonlet Erythrodiplax berenice

  28. Needham’s Skimmer Libellula needhami

  29. Midge Predators • Swallows and Swifts • Forage on mating swarms • Bats • Feed in open areas

  30. Looking ahead … • Monitor beneficial organisms • Vertebrates • Invertebrates • Promote scientific research • Local schools • UMass Boston (Biology, ECOS)? • Adapt

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