| 1. |
- Baird, Emily, et al.
(författare)
-
Bearing selection in ball-rolling dung beetles: is it constant?
- 2010
-
Ingår i: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. - : Springer Science and Business Media LLC. - 1432-1351. ; 196, s. 801-806
-
Tidskriftsartikel (refereegranskat)abstract
- Ball rolling in dung beetles is thought to have evolved as a means to escape intense inter- and intra-specific competition at the dung pile. Accordingly, dung beetles typically roll along a straight-line path away from the pile, this being the most effective escape strategy for transporting dung to a suitable burial site. In this study, we investigate how individual diurnal dung beetles, Scarabaeus (Kheper) nigroaeneus, select the compass bearing of their straight-line rolls. In particular, we examine whether roll bearings are constant with respect to geographic cues, celestial cues, or other environmental cues (such as wind direction). Our results reveal that the roll bearings taken by individual beetles are not constant with respect to geographic or celestial references. Environmental cues appear to have some influence over bearing selection, although the relationship is not strong. Furthermore, the variance in roll bearing that we observe is not affected by the presence or absence of other beetles. Thus, rather than being constant for individual beetles, bearing selection varies each time a beetle makes a ball and rolls it away from the dung pile. This strategy allows beetles to make an efficient escape from the dung pile while minimizing the chance of encountering competition.
|
|
| 2. |
- Dacke, Marie, et al.
(författare)
-
Dung Beetles Use the Milky Way for Orientation
- 2013
-
Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 23:4, s. 298-300
-
Tidskriftsartikel (refereegranskat)abstract
- When the moon is absent from the night sky, stars remain as celestial visual cues. Nonetheless, only birds [1, 2], seals [3], and humans [4] are known to use stars for orientation. African ball-rolling dung beetles exploit the sun, the moon, and the celestial polarization pattern to move along straight paths, away from the intense competition at the dung pile [5-9]. Even on clear moonless nights, many beetles still manage to orientate along straight paths [5]. This led us to hypothesize that dung beetles exploit the starry sky for orientation, a feat that has, to our knowledge, never been demonstrated in an insect. Here, we show that dung beetles transport their dung balls along straight paths under a starlit sky but lose this ability under overcast conditions. In a planetarium, the beetles orientate equally well when rolling under a full starlit sky as when only the Milky Way is present. The use of this bidirectional celestial cue for orientation has been proposed for vertebrates [10], spiders [11], and insects [5, 12], but never proven. This finding represents the first convincing demonstration for the use of the starry sky for orientation in insects and provides the first documented use of the Milky Way for orientation in the animal kingdom.
|
|
| 3. |
- Smolka, Jochen, et al.
(författare)
-
A new galloping gait in an insect
- 2013
-
Ingår i: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 23:20, s. 913-915
-
Tidskriftsartikel (refereegranskat)abstract
- An estimated three million insect species all walk using variations of the alternating tripod gait. At any one time, these animals hold one stable triangle of legs steady while swinging the opposite triangle forward. Here, we report the discovery that three different flightless desert dung beetles use an additional gallop-like gait, which has never been described in any insect before. Like a bounding hare, the beetles propel their body forward by synchronously stepping with both middle legs and then both front legs. Surprisingly, this peculiar galloping gait delivers lower speeds than the alternating tripod gait. Why these beetles have shifted so radically away from the most widely used walking style on our planet is as yet unknown.
|
|
