Bug on my friends dog
I forwarded your picture and email to Penn State Entomology. I'll let you know as soon as I hear back from them.
Very cool! This is a deer ked (Lipoptena cervi).
Deer keds are external parasites that, as the name implies, preferentially feed on deer. However, they sometimes land on the wrong host, which can include dogs, cattle, and humans. Dogs are reasonably well known hosts in Europe but haven't been recorded as hosts in the US, so it's interesting to confirm that deer keds colonize them here as well.
Adult keds emerge in the fall, fly to a host and shed their wings. After they shed their wings, they can only transfer hosts during close contact (e.g., during mating, feeding young, or hunters dressing harvested deer).
Half a dozen tick-borne pathogens have been sequenced from deer keds, but it's unclear if they can vector the pathogens or the pathogens are just in the last blood meal the keds took before being tested.
I'm conducting a collaborative research project at Penn State and we are actively soliciting deer keds from deer hunters and anyone else who finds them. I'd love to include your specimen in our study, so if you're willing to send it our address is
Insect ID Lab
501 Agricultural Science & Industries Building
University Park, PA, 16802