Parasitic bat fly fitness and survival after

separation from host

Lauren GoldbergerUniversity of California,

Santa Barbara

Dipteran Ectoparasites

• 2 Different Families– Streblidae: winged adults– Nycteribiidae: wingless adults (mostly found on insectivorous bats)

• Obligate ectoparasites = external parasites that cannot complete their life cycle when removed from a host.

Diptera: Streblidae

Bat Fly Life Cycle

• Take blood meals up to eight times per hour.• Female fly fosters larval instars internally.• Female leaves bat and deposits single larva on bat’s roosting substrate.• Larva immediately pupates and searches for a

host.

Question and HypothesesQuestion•What characteristics of bat flies increase or reduce their fitness as parasites on the hosts?Expectations•Larger flies will survive longer after separation from their bat host due to larger energy reserves. •Dense aggregations of flies on a host will increase competition and reduce survival time of the flies.Why Do We Care?•Many studies published on the effects of ectoparasites on bats, very few studies on the parasites themselves.

Methods• Mist-netted bats for 11

nights total (4 hrs/night) in Peñas Blancas and Monteverde.

• Processing bats:– Weighed bats using a spring

scale– measured forearm length– identified species of each bat.

Methods• Removed flies with soft

tweezers and placed each parasite into individual eppendorf tubes.

• Waited for flies to die (checked every 20 mins.)

• dissecting scope = measured body length with a micrometer.

• compound scope = looked for hyperparasitic fungal hyphae.

Diptera: Nycteribiidae

Results and Discussion

• 38 bats caught – 13 species and 7

genera – 11 females, 27 males

• 34 total bat flies– 30 Streblids– 4 Nycteribiids

• Average Parasite Abundance = 1.39

• Males likely have fewer parasites by absence of transmission– Social groups of several females and few males– Maternity colonies – Solitary males

• Female bats have 1-7% larger bodies—more resources and larger habitat.

• Removal of outlier (1.8, 14) gives R2 = 0.54• Fitness advantage of size: increased survival time due to

larger energy reserves• Fitness disadvantage of size: more easily recognized

(allogrooming)

• No observed correlation between ectoparasite abundance and fly survival time. – Ectoparasite abundances were lower than I anticipated– Flies most likely had sufficient resources, lack of

intraspecific competition.

Nycteribiid vs. Streblid Survival

• Nycteribiid flies ( =42.5 hrs. ) survived significantly x̄&longer than Streblid bat flies ( =5.7 hrs.) after x̄&separation.

• Can be explained by mode of transportation=– Nycteribiidae: no wings; forced to crawl– Streblidae: winged, most can fly (faster than crawling)

Diptera: StreblidaeDiptera: Nycteribiidae

Future Research• No observed Laboulbeniales fungal hyphae acting as

hyperparasites– Presence of hyperparasitism is documented in flies.– Might need larger sample size and higher microscope

magnification to observe hyperparasitism and look for relationship to survival time.

• Two pairs of flies were observed copulating on host and survived shorter period of time (not significant).– Use energy for courtship, smaller energy reserves.– Need further research and larger sample size

Acknowledgments

• Federico Chinchilla• Sofía Arce Flores• Estación Biológica

Monteverde• Natalie Sánchez• Eladio Cruz • My batty comrades: Shohei

Burns and Denisse Ruiz

Thank you to all of the people who helped me along the way, making my project possible