昆虫群落.pptx

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,#,How much water is there on Earth?,Habitats,and Communities,Marine systems:three major zones,Off shore or open sea,Neritic or near shore,Intertidal alternately submerged and exposed,Few insects,some of great interest discuss later,Devoid of insects,Habitats,and Communities,Estuaries:brackish water,Ecotone between inland water and the sea,Richer aquatic insect fauna than marine,Habitats,and Communities,Lotic:inland running water,Crenal spring fed headwaters,Rhithral streams and small rivers,Potamal large rivers,Highest diversity of aquatic insects,Habitats,and Communities,Lentic:inland standing water,Lacustrine lakes and ponds,Palustrine marshes and swamps,Shallow habitats,Ecotones between aquatic and terrestrial,Greatest insect diversity associated with vegetation,Habitats,and,Communities,Subterranean waters:Hypogean,Troglal caves,Stygal groundwater,Relatively sparse insect communities except were merging with surface waters,Habitats,and,Communities,Biotic Community:,Comprises all populations in a given habitat-including everything from bacteria to vertebrates and higher plants,Habitats,and,Communities,“Planktonic Community”,Plankton organisms that remain suspended,Adaptations for vertical migration and/or to remain at certain depths,Few insects adapted to planktonic existence,Habitats,and,Communities,“Nektonic Community”,Nekton Strong swimmers not at the mercy of the currents.,Few insect representatives,Habitats,and,Communities,“Pleustonic Community”,Pleuston Organisms at air-water interface,Atmospheric breathers that require aqueous medium for other needs,Habitats,and,Communities,“Benthic Community”,Benthos organisms associated with substratum,Bottom materials,plant beds,logs or other solid surfaces,Lentic Freshwaters,Lakes provide diverse habitats for aquatic insects,Environmental conditions,Distinct spatial gradients,Temporal changes pronounced,Aquatic insect communities change w/gradients in lakes and between lake types,Lake Zonation,Limnetic Zone open water devoid of rooted vegetation,Littoral Zone shallow marginal areas characterized by rooted vegetation,Sublittoral Zone transition between well-illuminated upper strata and Profundal Zone,Profundal Zone light insufficient for photosynthesis,Lake Zonation,Lake Communities,Pleuston:organisms associated with surface film,Epipleuston upper surface,Water striders,Hypopleuston lower surface,Meropleuston not continuous resident,Mosquito larvae,Lake Communities,Pleuston:,Adaptations for surface residence,Small size,Furcula,Collembola,Hydrophobic cuticle,Gyrinids have hydrophobic dorsum and wettable venter,Lake Communities,Pleuston:,Three families of Hemiptera=striders,Hydrometridae elongate body and legs,Water measurer,Gerridae and Veliidae,Supported by full length of tarsi,Tarsi covered with“hairpiles”,Secrete substance that lowers surface tension,Lake Communities,Pleuston:,Diptera limited to mosquitoes,Hydrophilid beetles“walk”inverted on underside of water surface,Lake Communities,Plankton:,Insects poorly represented,Chaoboridae only planktonic insect,Lake Communities,Chaoboridae:,World wide,Lakes and ponds,Nearly transparent,Prehensile antennae,Feed on zooplankton and mosquitoes,Lake Communities,Chaoborus,:,Tracheal system reduced to kidney shaped air sacs,One pair thoracic;another in abdomen,Use these“hydrostatic organs”to adjust buoyancy,Lake Communities,Chaoborus,:,2 types of vertical migration,Full generally in lake species,Reside in bottom mud during day,Feed in water column at night,Reduced predominately in pond species=Remain in epilimnion,Lake Communities,Chaoborus,:,Limited migration of some species may explain why they are missing from lakes with fish(,C.americanus,),Others coexist with fishes(full),and are found in fishless lakes(reduced;,C.flavicans,),Lake Communities,Chaoborus,:,Different larval instars exhibit different migratory behavior,C.trivittatus,1,st,and 2,nd,instars restricted to surface water,3,rd,and 4,th,move to deeper water during day,Smallest at surface,size,with depth,Lake Communities,Chaoborus,:,Regular depth distribution of size classes apparently related to food size distribution and predation,Larger items generally deeper,Greater vulnerability to visual predation,Lake Communities,Chaoborus,:,Light=entraining agent,Benthic&planktonic phases can be artificially reversed in lab,instars react differently,Lake Communities,Chaoborus,:,Oxygen=entraining agent,High 0,2,1%migrated,Low 0,2,30%migrated,Lake Communities,Chaoborus,:,Horizontal migration,Spring migration of larvae to littoral zone,Adaptation enabling exposure to warm water prior to pupation,cfb.unh.edu/CFBkey/html/movies.html#,Lake Communities,Chironomidae:,1,st,instar adapted to planktonic existence for dispersal,Larvae positively phototactic 1-3 days,Vertical migrations common w/diel light,As larvae mature shift from photophilous to photophobic,Lake Communities,Chironomidae:,Late instars may again enter plankton,Move to well-aerated water,In some species,late instar individuals follow pattern described for 1,st,instars,Lake Communities,Ranatra montezuma:,Hemipteran,Nocturnal planktonic behavior,As light drops below 100 lux,move from littoral to limnetic zone,Feed on,Hyalella montezuma,return to littoral zone during day,Lake Communities,Nekton:,Nekton distinguished from plankton by directional mobility;from benthos by association with open water,Although many aquatic insects swim,they are associated with hard substrate,Lake Communities,Nekton:,Truly nektonic species restricted to a few hemipterans and coleopterans,Hemiptera nektonic species include Notonectidae,Corixidae and Belostomatidae,Lake Communities,Nekton:,Anisops,and,Buenoa,(Notonectidae)use hemoglobin to control buoyancy,Prey on small arthropods in open water column,Lake Communities,Nekton:,Relationship between habitat and leg structure,Buenoa,open water,Hind legs for,rapid pursuit,Forelegs and midlegs for prey capture,Lake Communities,Nekton:,Relationship between habitat and leg structure,Notonecta,underside of surface film,Feed on moving prey as well as those caught in surface film,Leg structure is intermediate,Lake Communities,Nekton:,Corixidae,Elongate,flattened,hair-fringed hindlegs,Most restricted to water 1 m,Planktivorous spp.are nektonic,Lake Communities,Nekton:,Belostomatidae,Most are sit and wait predators,Lethocerus,=nekton,Coleoptera,Only largest Dytiscidae and Hydrophilidae,Lake Communities,Benthos:,Majority of insects in lentic habitats are benthic,Collectively,aquatic insects make up to 90%of total benthic fauna,Lake Communities,Benthos:,Several orders have highest diversity and abundance in lentic habitats,Odonata(dragonflies),Hemiptera,Coleoptera,Diptera(some families exclusively lentic),Hymenoptera,Lepidoptera,Neuroptera,Lake Communities,Benthos:,The composition and relative abundance of aquatic insects is integrated along depth profiles,Lake Communities,Benthos:,Hutchinson-insect fauna of lakes fall into three depth categories,Aquatic adults that never developed gills,Hemipterans and coleopterans,Rarely occur in water depth more than 3 m,Most surface for air,Lake Communities,Benthos:,Hutchinson-insect fauna of lakes fall into three depth categories,All other orders with exception of Diptera,Amphibiotic(aquatic larva,terrestrial adult),Extract O,2,from water,Restricted to relatively shallow water,Lake Communities,Benthos:,Hutchinson-insect fauna of lakes fall into three depth categories,Only certain dipterans have colonized profundal zone,Amphibiotic,Chaoboridae,Chironomidae,Lake Communities,Taxonomic richness of benthic insect communities declines with depth,Max richness at depths of 1-2 m,Exam topics,Hoeinghaus et al.2007,Which river concept explains energy sources in 10 tribs of Parana river?,Low-gradient,high gradient,reservoirs,C,N isotopes for fishes,molluscs,plants,detritus,Big conclusions?,Lowland river foodwebs=C from aquatic macrophytes,Reservoirs=C from algae more important,High gradient rivers=C from filamentous algae,Relate to river concept?,Lytle and Poff 2004,Adaptations to survive floods and droughts,ID adaptations,Modes:know examples,Timing of flow=life history adaptations,Predictability=behavioral adaptations,Magnitude/freq=morphological adaptations,Human impacts,Stone et al.2005,Macroinvertebrates of ag streams,What variables impact them?,Methods?Sites?Sampling?What attributes were compared?,Which attributes varied with physical variables?,What impacts caused low scores for macroinvertebrates?,Merritt and CummingsChapter 3 Sampling,Devices,Sorting,preservation,Taxonomic resolution,Merritt and CummingsChapter 5 Habitat,life history,Marine paradox,Hydraulics,Habitats,Upstream movements,