Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetles
<p>Abstract</p> <p>Background</p> <p>In the Namib Desert fog represents an alternative water source. This is utilised by Darkling beetles (Tenebrionidae) that employ different strategies for obtaining the fog water. Some dig trenches in the sand, while others use their...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2010-07-01
|
| Series: | Frontiers in Zoology |
| Online Access: | http://www.frontiersinzoology.com/content/7/1/23 |
| _version_ | 1811286866501042176 |
|---|---|
| author | Dacke Marie Nørgaard Thomas |
| author_facet | Dacke Marie Nørgaard Thomas |
| author_sort | Dacke Marie |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>In the Namib Desert fog represents an alternative water source. This is utilised by Darkling beetles (Tenebrionidae) that employ different strategies for obtaining the fog water. Some dig trenches in the sand, while others use their own bodies as fog collectors assuming a characteristic fog-basking stance. Two beetle species from the genus <it>Onymacris </it>have been observed to fog-bask on the ridges of the sand dunes. These beetles all have smooth elytra surfaces, while another species with elytra covered in bumps is reported to have specialised adaptations facilitating water capture by fog-basking. To resolve if these other beetles also fog-bask, and if an elytra covered in bumps is a more efficient fog water collector than a smooth one, we examined four Namib Desert beetles; the smooth <it>Onymacris unguicularis </it>and <it>O. laeviceps </it>and the bumpy <it>Stenocara gracilipes </it>and <it>Physasterna cribripes</it>. Here we describe the beetles' fog-basking behaviour, the details of their elytra structures, and determine how efficient their dorsal surface areas are at harvesting water from fog.</p> <p>Results</p> <p>The beetles differ greatly in size. The largest <it>P. cribripes </it>has a dorsal surface area that is 1.39, 1.56, and 2.52 times larger than <it>O. unguicularis</it>, <it>O. laeviceps</it>, and <it>S. gracilipes</it>, respectively. In accordance with earlier reports, we found that the second largest <it>O. unguicularis </it>is the only one of the four beetles that assumes the head standing fog-basking behaviour, and that fog is necessary to trigger this behaviour. No differences were seen in the absolute amounts of fog water collected on the dorsal surface areas of the different beetles. However, data corrected according to the sizes of the beetles revealed differences. The better fog water harvesters were <it>S. gracilipes </it>and <it>O. unguicularis </it>while the large <it>P. cribripes </it>was the poorest. Examination of the elytra microstructures showed clear structural differences, but the elytra of all beetles were found to be completely hydrophobic.</p> <p>Conclusions</p> <p>The differences in fog water harvesting efficiency by the dorsal surface areas of beetles with very different elytra surface structures were minor. We therefore conclude that the fog-basking behaviour itself is a more important factor than structural adaptations when <it>O. unguicularis </it>collect water from fog.</p> |
| first_indexed | 2024-04-13T03:08:33Z |
| format | Article |
| id | doaj.art-53ad735daeef4379a7cd1d43c60e30ac |
| institution | Directory Open Access Journal |
| issn | 1742-9994 |
| language | English |
| last_indexed | 2024-04-13T03:08:33Z |
| publishDate | 2010-07-01 |
| publisher | BMC |
| record_format | Article |
| series | Frontiers in Zoology |
| spelling | doaj.art-53ad735daeef4379a7cd1d43c60e30ac2022-12-22T03:05:10ZengBMCFrontiers in Zoology1742-99942010-07-01712310.1186/1742-9994-7-23Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetlesDacke MarieNørgaard Thomas<p>Abstract</p> <p>Background</p> <p>In the Namib Desert fog represents an alternative water source. This is utilised by Darkling beetles (Tenebrionidae) that employ different strategies for obtaining the fog water. Some dig trenches in the sand, while others use their own bodies as fog collectors assuming a characteristic fog-basking stance. Two beetle species from the genus <it>Onymacris </it>have been observed to fog-bask on the ridges of the sand dunes. These beetles all have smooth elytra surfaces, while another species with elytra covered in bumps is reported to have specialised adaptations facilitating water capture by fog-basking. To resolve if these other beetles also fog-bask, and if an elytra covered in bumps is a more efficient fog water collector than a smooth one, we examined four Namib Desert beetles; the smooth <it>Onymacris unguicularis </it>and <it>O. laeviceps </it>and the bumpy <it>Stenocara gracilipes </it>and <it>Physasterna cribripes</it>. Here we describe the beetles' fog-basking behaviour, the details of their elytra structures, and determine how efficient their dorsal surface areas are at harvesting water from fog.</p> <p>Results</p> <p>The beetles differ greatly in size. The largest <it>P. cribripes </it>has a dorsal surface area that is 1.39, 1.56, and 2.52 times larger than <it>O. unguicularis</it>, <it>O. laeviceps</it>, and <it>S. gracilipes</it>, respectively. In accordance with earlier reports, we found that the second largest <it>O. unguicularis </it>is the only one of the four beetles that assumes the head standing fog-basking behaviour, and that fog is necessary to trigger this behaviour. No differences were seen in the absolute amounts of fog water collected on the dorsal surface areas of the different beetles. However, data corrected according to the sizes of the beetles revealed differences. The better fog water harvesters were <it>S. gracilipes </it>and <it>O. unguicularis </it>while the large <it>P. cribripes </it>was the poorest. Examination of the elytra microstructures showed clear structural differences, but the elytra of all beetles were found to be completely hydrophobic.</p> <p>Conclusions</p> <p>The differences in fog water harvesting efficiency by the dorsal surface areas of beetles with very different elytra surface structures were minor. We therefore conclude that the fog-basking behaviour itself is a more important factor than structural adaptations when <it>O. unguicularis </it>collect water from fog.</p>http://www.frontiersinzoology.com/content/7/1/23 |
| spellingShingle | Dacke Marie Nørgaard Thomas Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetles Frontiers in Zoology |
| title | Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetles |
| title_full | Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetles |
| title_fullStr | Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetles |
| title_full_unstemmed | Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetles |
| title_short | Fog-basking behaviour and water collection efficiency in Namib Desert Darkling beetles |
| title_sort | fog basking behaviour and water collection efficiency in namib desert darkling beetles |
| url | http://www.frontiersinzoology.com/content/7/1/23 |
| work_keys_str_mv | AT dackemarie fogbaskingbehaviourandwatercollectionefficiencyinnamibdesertdarklingbeetles AT nørgaardthomas fogbaskingbehaviourandwatercollectionefficiencyinnamibdesertdarklingbeetles |