Age dominates flight distance and duration, while body size shapes flight speed in Bombus terrestris L. (Hymenoptera: Apidae)

Flight plays crucial role in the fitness of insect pollinators, such as bumble bees. Despite their relatively large body size compared to their wings, bumble bees can fly under difficult ambient conditions, such as cooler temperatures. While their body size is often positively linked to their foraging range and flight ability, the influence of age remains less explored. Here, we studied the flight performance (distance, duration, and speed) of aging bumble bee workers using tethered flight mills. Additionally, we measured their intertegular distance (ITD) and dry mass as proxies for their body size. We found that flight distance and duration was predominantly influenced by age, challenging assumptions that age does not play a key role in foraging and task allocation. From the age of 7 to 14 days, flight distance and duration increased six-fold and five-fold, respectively. Conversely, body size primarily impacted the maximum and average flight speed of workers. Our findings indicate that..., Experimental overview
The experiment was designed based a pilot study, in which the flight performance of differently aged workers from two colonies had been examined in the previous year. In this study, we repeatedly measured the individual flight performance of 61 workers from four colonies (n = 14, 18, 8 and 21 workers per colony) at the age of 7, 14 and 21 days. Due to occasional difficulties in locating every marked worker on each day of measurement or potential mortality (n = 13/77), or instances where a few workers had lost their tags during flight measurement (n = 5/77), these individuals were excluded from data analysis. We selected workers with a wet body mass ranging from 100 mg to 320 mg, primarily during the colony’s exponential growth phase. 
Bumble bee husbandry
We used four commercial, queenright Bombus terrestris colonies (Natupol Research Hives, Koppert B.V., Netherlands) with approximately 20-30 workers. They were housed in their standard plastic nest boxes (27 [l] x ..., , # Age dominates flight distance and duration, while body size shapes flight speed in *Bombus terrestris* L. (Hymenoptera: Apidae)

## Description of the data and file structure

The data table contains the entire dataset on which our statistical analysis is based.

**Data2023.csv**

Variables are as follows:

Date = date on which the bee was tested in flight mill

Bee = bee ID

Age = bee age (days) as numerical

AGE = bee age (days) as factor

Colony = colony name

BeeMass = bee weight before flight (mg)

Start = flight start time (h:min:s)

Distance = flight distance (m)

Duration = flight duration (s)

Speed = mean flight speed (m/s) throughout the entire flight

MaxSpeed = maximum flight speed (m/s) throughout the entire flight

Temp = mean room temperature throughout the entire flight 

ITD = intertegular distance (mm)

TagPos = deviation of tag position from the center (%) (see methods for a detailed description)

WetMass = sample bee weight (mg) after storage at -20°C

DryMas...