Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Biology

First Advisor's Name

Dr. Jamie Theobald

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Dr. Suzanne Koptur

Second Advisor's Committee Title

committee member

Third Advisor's Name

Dr. Philip Stoddard

Third Advisor's Committee Title

committee member

Fourth Advisor's Name

Dr. Matthew DeGennaro

Fourth Advisor's Committee Title

committee member

Fifth Advisor's Name

Dr. Robert Lickliter

Fifth Advisor's Committee Title

committee member

Keywords

optic flow, attention, drosophila melanogaster, flight control

Date of Defense

6-22-2021

Abstract

To successfully navigate the complex visual world, animals must extract relevant information from the deluge of light-carried signals that arrive at their eyes. Early vision filters are passive, energy-saving gates that block out irrelevant signals. The remaining incoming signals are then subject to active filtering by visual attention systems which are energetically expensive, especially for smaller animals, which are subject to similar survival challenges as larger animals.

Among visual behaviors performed by insects, flight stabilization demands one of the highest rates of information uptake. Flying insects must quickly respond to flight disturbances to avoid navigation errors and collisions. Active flight is energy-intensive, but the variable environmental and flight conditions make passive filtering unreliable to infer self-motion.

Dipterans (flies and mosquitoes) are a prosperous order of insects that owe their success to impressive flying skills. Though many visual adaptations for flight have been well characterized, little research has been dedicated to the active attention processes required for flight stabilization. In this dissertation, I investigated how the visual attention systems of fruit flies work to maximize relevant information uptake during flight. I have focused on three main questions: (1) Do flies shift attention away from regions impacted heavily by motion-blur? (2) Do flies’ attention systems prioritize regions with higher quality images? (3) Does the attention system only filter noisy regions, or does it weigh the regional image quality against other sources of information present?

I used a virtual reality flight arena to convince stationary, tethered fruit flies that they were actually flying. I tested whether flies were attentive to visual regions by showing local perturbations and measuring corrective steering responses. I found that fast-flying flies (1) shift their attention to the slower frontal parts of their visual field; (2) shift their attention forward when flying in dim and low contrast environments; (3) weigh other relevant information with image clarity. My findings provide a better understanding of how the energy-limited visual systems of fruit flies can process all the information required to stabilize flight.

Identifier

FIDC010287

ORCID

https://orcid.org/0000-0001-7244-8830

Previously Published In

Palermo, N., & Theobald, J. (2019). Fruit flies increase attention to their frontal visual field during fast forward optic flow. Biology letters, 15(1), 20180767.

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