Mapa mental
15 - Chiroptera
Contenido del mapa
15 - Chiroptera
diversity & specialization
- 202 genera, 1,120 species - second only to RODENTS
- specialized feeding, reproduction, behavior, morphology
- flight allowed WIDE GEOGRAPHIC distribution
- fill many feeding niches
- mostly INSECTIVOROUS
- but also carnivorous, piscivorous, nectarivorous, frugivorous, or sanguinivorous
- varied reproductive approaches: -sperm storage -delayed fertilization
- 1 or 2 young per year
- roost in various sites
- solitary or communal
- mostly NOCTURNAL, except island-dwelling megabats
- for size, very LONG-LIVED (30+ years)
major differences between bat suborders
- microchiropterans
- echolocation
- mostly insectivorous
- tragus is well-developed
- nose or facial ornamentation
- generally SMALL body size
- small eyes
- modified cervical vertebrae
- head flexed DORSALLY when roosting
- tail and uropatagium present
- postorbital process usually ABSENT
- echolocating bats, microbats
- Vespertilionidae
- ~30 species
- "Evening" or "vesper" bats
- "plainnose" bats
- most WIDESPREAD family worldwide
- some colonial, some solitary, migratory, or resident
- mostly INSECTIVOROUS
- Molossidae
- 6 species
- ALL insectivores
- MOST are fast-flying ariel insectivorous
- LARGE colonies (up to 20 million holy shit)
- guano deposition
- Mormoopidae
- 1 species
- "leaf-chinned" or "ghost-faced" bats
- insectivorous
- colonial
- Phyllostomidae
- 4 species
- "leaf-nosed" bats
- wide food habits
- insectivorous, carnivorous, nectarivorous, frugivirous, sanguinivorous
- forelimbs for FLIGHT and in some species, CLIMBING or FOOT HANDLING
- megachiropterans
- almost NO echolocation
- fruit or nectar eaters
- NO tragus
- NO nose or facial ornamentation
- generally LARGE body size
- LARGE eyes
- NO modification of cervical vertebrae
- head VENTRAL when roosting
- tail and uropatagium usually ABSENT
- postorbital process is WELL DEVELOPED
- Old World fruit bats, megabats
- Pteropodidae
- flying foxes, fruit-eating bats
- large ears, eyes
- flat-crowned molars for crushing fruit
- crepuscular or diurnal, can not fly in total darkness
- Ethiopian, Oriental, and Australian regions only
- microchiropterans
morphology
- only VOLANT mammals
- pectoral area is MODIFIED
- fusion of last C and 1st 2 T vertebrae
- t-shaped manubrium
- STRONG RIBS for anchoring wings
- wing from skin (aka patagium) is stretched between ARM, WRIST, and FINGER bones
- patagium is THIN but RESISTANT TO TEARS and quick-healing
- bones of arms and hands ELONGATE and SLENDER
- flight membranes: -plagiopatagium, chiropatagium, uropatagium (calcar may be present), and propatagium
- modified SHOULDER LOCK in many species
- flight muscles arranged for increased maneuverability
- relatively SLOW but highly MANEUVERABLE
- wings provide both THRUST and LIFT
- wing profile is ASYMMETRICAL
- unequal pressures above and below wing generate LIFT
- flight
- bats have relatively LOW wing loading (aka ratio of body weight to wing area)
- many bats have LOW aspect ratio wings (aka ratio of wing span to wing chord)
- downstroke is POWER stroke
- wing tips TWIST and provide additional thrust
- upstroke is RECOVERY stroke
- sensing the environment
- nearly all bats have functional vision
- eyes LARGE in megabats
- visual acuity secondary in MICROBATS
- high-frequency acoustic orientation and audible vocalizationprimary means
- ECHOLOCATION: the process of emitting sounds and using information from returning echoes to sense the surrounding environment
fossil history
- Icaronycteris
- early EOCENE, ~52 million years ago
- claws on first two wing digits
- tiny remnants of claws on other hand digits
- long HUMERUS
- short, broad wings
- could probably ECHOLOCATE
- bony adaptations of hyoid and ear region present
- 2 Main Clades
- Yinpterochiroptera
- Yangochiroptera
- Icaronycteris
economics & conservation
- benefits outweight negatives
- most significant predator of nocturnal pest insects
- pollinate ~200 economically imported plants
- GUANO for fertilizer and gunpowder
- medical research
- population declines and range reductions
- cave enclosures, destruction
- loss of foraging or ROOSTING habitats (snags)
- siltation or DRAINING of riparian areas
- insecticide accumulation
- pathogens/disease, including white-nose syndrome
- changing perceptions of bats is KEY to conservation
- Negatives
- Bacterial, rickettsial, viral, and fungal diseases
- Rabies in <1-4% of members of the population (well below that seen in skunks, foxes, dogs, raccoons)
- loss of LIVESTOCK to disease transmitted by vampires