Adaptions of bats to cope with the climate of a mountain forest. Hannah Burger, Mariella Neuhäuser, Ann-Marie Rottler

Transcription

1 Adaptions of bats to cope with the climate of a mountain forest Hannah Burger, Mariella Neuhäuser, Ann-Marie Rottler Curso tropical en Costa Rica 2005

2 Background Bats are homoiotherm and able to regulate their body temperature e.g. Vespertilionidae cool down in winter to 4 C (torpor) Body temperature of Phyllostomidae relatively constant Climate of Mountain forest: humid and cold

3 Question Is there any relation between the length and structure of the coat to the body size and area?

4 HYPOTHESIS Coat of bats is adapted to the climate conditions of a mountain forest. We expect that smaller bats have denser and longer hair in adaption to the cold climate because of the disadvantageous surface-body mass relation.

5 Location: Methods San Ramón National Park Costa Rica Mountain forest 840 m a.s.l. Research work: 1. Bat capture with mist nets during 3 nights 2. Identification and measurements of the bats Pteronotus parnellii

6 Methods Recording following parameters Determine the species Reproductive status Age Weight Length of forearm Length of the hair Cut some hair for analysis Put bat on a sheet and draw the outline of wing and body

7 Results our bats 7 species, 26 captures Phyllostomidae Phyllostominae Carollia brevicauda Stenodermatinae Artibeus toltecus Artibeus jamaicensis Sturnira ludovici Sturnira mordax frugivor Vespertilionidae Myotis nigricans Mormoopidae Pteronotus parnellii insectivor

8 M. nigricans C. brevicauda A. toltecus P. parnellii S. ludovici S. mordax A. jamaicensis Results Analysis Gewicht [g] Unterarml. [mm] Flügeloberfläche [cm²]

9 Myotis nigricans M. nigricans C. brevicauda A. toltecus P. parnellii S. ludovici S. mordax A. jamaicensis Gewicht [g] Unterarml. [mm] Flügeloberfläche [cm²] Artibeus jamaicensis

10 Results - Analysis of hair Coat is very dense Partly interspecific variations in hair structure ( bristles mixed with thin hair) Wet coat dries very fast Uropatagium of highland species like Sturnira sp. also hairy

11 Results length of hair 1. intraspecific difference in the length of hair 14 Felllänge [mm] a b b Bauch Nacken Rücken ANOVA: n=26 H=49,31 p<0, No interspecific difference in the length of hair

12 Results Relation wing area body area Körperoberfläche [cm²] large wing area in comparison to the body area Flügeloberfläche [cm²] Phyllostomidae Vespertilionidae Mormoopidae Trendlinie

13 Discussion length and structure of hair 1. Very dense hair Adaptions to the cold and humid climate of a mountain forest 2. Significant difference between the length of hair on front and back Some Phyllostomidae roost belly to belly probably to warm each other

14 Discussion length and structure of hair 3. No interspecific difference in absolute hair length small species have the same length of hair as bigger ones however, smaller species have longer hair in relation to their body size and area adaption to the disadvantagous surface body mass relation to reduce heat loss

15 Discussion big wings in comparison to the body area Wings and environment have similar temperature No heat loss through the wings

16 Conclusions There exist probably adaptions to the cold and humid climate of a mountain forest: dense, probably insolating and water rejecting coat small species have longer hair in relation to their body size and area small body in relation to the wings probably to reduce heat loss

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