Photoresponses of late instar Chaoborus punctipennis larvae to UVR
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588; e-ISSN 1573-5125, more
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| Keywords |
Behaviour > Avoidance reactions
Behaviour > Orientation behaviour > Taxis > Phototaxis
Detection
Radiations > Electromagnetic radiation > Ultraviolet radiation
Chaoborus punctipennis
Fresh water |
| Authors | | Top |
- Persaud, A.D.
- Arts, M.T.
- Yan, N.D.
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| Abstract |
With a few clear exceptions (e.g., Daphnia) it is uncertain if most aquatic invertebrates can detect and respond to ultraviolet radiation (UVR). It is known that many aquatic invertebrates are vulnerable to UVR and that anthropogenically-induced increases in surface UVR have occurred in recent decades. We examined the photoresponses of late larval instars of Chaoborus punctipennis to different combinations of UVA (320-400 nm), UVB (300-320 nm) and visible light (400-700 nm) to determine whether the larvae can detect and/or avoid UVR. To accomplish this, we exposed late instar C. punctipennis larvae to a directional light source of UVR only (peak wavelength at 360 nm), visible light only or visible plus various wavebands of UVR. We examined negative phototaxis for 10 min at a quantum flux of 2.62 x 1013 quanta s-1 cm-2 (S.D. = 3.63 x 1012 quanta s-1 cm-2). In the dark, larvae stayed close to the surface of the experimental vessels. Under all treatments containing visible light the larvae exhibited negative phototaxis and occupied the bottom of the vessels. Under UVR only, the larvae occupied the middle of the water column. Our results suggest that late instar C. punctipennis larvae are unable to detect and avoid UVB and short UVA wavelengths but they can detect long UVA wavelengths. |
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