Objectives
The objective of the expedition to the Society and Marquesan archipelagoes was to determine the nature and diversity of the spider fauna of French Polynesia, and identify possible threats. Over the last 12 years we have been studying the extensive radiations of the spider genera Tetragnatha, Theridion, and a few other groups in the Hawaiian Islands. The spiders in French Polynesia appear to belong to similar groups, and it is almost certain that there has been a radiation of species in at least some of these groups, although information is sparse. We set out to collect representative species from different islands throughout French Polynesia. We intend to generate phylogenetic (or genealogical) patterns of relationship for different groups of spiders in French Polynesia using morphological and various molecular approaches. Using this information, we can test the role of ecological and behavioral attributes in dictating how these spiders form new species. In addition to understanding the ecological and behavioral correlates associated with speciation in the group, we set out to examine the impact of alien species and different levels of disturbance on the native spiders of French Polynesia. In particular, we have been looking at the impact of ants in limiting the distribution of species in Hawaii, and our intention was to examine this issue in French Polynesia. In particular, what species of ants are important in limiting the distribution, and to what extent are species distributions limited by habitat destruction and other anthropogenic disturbance.
There were 3 primary achievements predicted: (1) Assessment of species identities, numbers of species, distributions, and abundance for the different spider groups in French Polynesia. (2) Assessment of the role of alien species and habitat destruction in limiting the distribution of species in the radiations, and possible management strategies for recovering populations. (3) Assessment of genealogical relationships amongst these species, and hence possible mechanisms governing species formation and evolutionary changes in distribution and abundance. Here we report on (1) and (2). Part (3) requires further study.
Background
The islands of the Society and Marquesan archipelagoes differ considerably in size, elevation, distance from the nearest continental landmass, and current population density:
|
|
Area (sq.km) |
Altitude (m) |
Nearest landmass (km) |
Pop.Density (persons/sq km) |
||
|
Island |
Group |
Continent |
||||
|
|
|
|
|
|
|
|
|
Tahiti |
1068.8 |
2241 |
25 |
400 |
6000 |
89.4 |
|
Moorea |
132 |
1207 |
25 |
400 |
6000 |
26.5 |
|
Raiatea |
173.3 |
1017 |
5 |
400 |
6000 |
27.8 |
|
Tahaa |
90.9 |
590 |
5 |
400 |
6000 |
36.4 |
|
Huahine |
82.1 |
669 |
30 |
400 |
6000 |
30.5 |
|
BoraBora |
21.9 |
727 |
20 |
400 |
6000 |
91.3 |
|
|
|
|
|
|
|
|
|
Nuku Hiva |
345 |
1186 |
40 |
600 |
7300 |
- |
|
Ua Huka |
82.4 |
856 |
40 |
600 |
7300 |
- |
|
Ua Pou |
111.6 |
1231 |
40 |
600 |
7300 |
- |
|
Hiva Oa |
318 |
1190 |
100 |
600 |
7300 |
- |
|
Tahuata |
70.8 |
1000 |
5 |
600 |
7300 |
7.1 |
Each of the parameters listed is of considerable importance to the evolution of the arthropod fauna in these islands, and the conservation status.
Prior to our expedition to the Marquesas, knowledge of the spider fauna of French Polynesia was limited largely to publications by Lucius Berland (Berland 1927, 1929, 1933, 1934a, 1934b, 1934c, 1935a, 1935b, 1935c, 1938, 1942) from the MNHN in Paris, with some of this information being summarized by Marples (1957). Berland (1934c) recognized 4 major subdivisions of the Pacific (see figure above): I. Australasia/ Papua New Guinea. II Polynesia. III Micronesia. IV Neotropical. V. Antarctic. Berland concludes: “The examination of the spiders of the Pacific thus seems to justify the subdivision as several provinces [see Figure 1]. All information seems to indicate that the settlement of Pacific was done by migrations coming from the Indo-Malaysian area, migrations which would probably have been multiple and following several distinct currents. One of these currents would have been populated from Australia; this is what I call the “australo-canaque” province; a quite distinct current of migration, but of same origin, would have populated Polynesia, whose current archipelagoes constitute probably only the subdivision of a previously more extended continent, with a branch being detached towards Hawaii; another towards Micronesia see Figure 2]. There is no visible relation between America and the Pacific; but on the other hand Galapagos as well as Fernandez received their fauna from the south of America, by the austral lands. In addition the islands of Pacific almost always present a very marked level of endemism, which testifies to an extremely old isolation, and should be fix their separation farther back, at least to about the middle of the Tertiary epoch, and perhaps farther. I will add that the study of several zoological groups, as one can see it in this work, arrive, independently from each other, at conclusions very close to mine, and so appear to me to receive a solid confirmation from it.”
As can be seen, Berland subscribed strongly to one of the popular views of the time, that the islands of Polynesia were formed as a single large continent, which became subdivided to form the islands as we now know them. Recent geological evidence has dismissed this view: The archipelagoes of Hawaii, Marquesas and Societies are all volcanic in origin, and formed as volcanic hot spots. All three archipelagoes exhibit a chronological arrangement of islands. In Hawaii, the islands range from Kauai, the oldest in the north at 5.1myrs, to Hawaii the youngest, in the south, at up to 0.4myrs old. The Marquesas range from Nuku Hiva , the oldest in the north at 3.7myrs, to Fatu Hiva the youngest, in the south, at 1.4myrs. The Society Islands range from Bora Bora, the oldest in the north at 3.3myrs, to Tahiti the youngest, in the south, at 1.0myrs.
Itinerary
June
16 f Left Berkeley
17 s (Moorea) Arrived Moorea
18 s (Moorea) Went up trail to 3 Coconuts Pass - Gillespie, Roderick, Garb, Spagna, Shapiro. Collected down steep bank to large river around 320m, and on river. Found lots of T. macilenta; also T. maxillosa on river. Found 2 immatures of Tetragnatha sp 4A. Also lots of pholcids, a few Leucauge Also collected on small river near pig farm on way back. Found lots of T. maxillosa.
19 m (Moorea) Looked around various dirt roads. Then up Paopao-Vaiare trail, coming in from Vaiare side - Gillespie, Roderick, Garb, Spagna, Shapiro.. Hiked up to top of ridge. Collected before dark along ridge. Collected in dark on way down. Got jumping spider, crab spider, 1 Tetragnatha sp 4A. Collected in dark on way down. Found LOTS of dictynids, pholcids. NO Tetragnatha; Argyrodes (“Ariamnes”) in local patches (almost all collected in one place, at about 250m).
20 t (Moorea) Roderick and Garb went up trail to 3 Coconuts Pass.
21 w (Nuku Hiva) Gillespie and Shapiro – flew to Nuku Hiva (arrived 2.30). Took 4WD to Mt. Muake, 864m above Taiohae. Collected on way up to the radio station. Camped on top. Vegetation initially conifer canopy (~780-810m), then a legume (Paraserionthes falcata) from about 810-830m, and then pretty bare and open at the summit. Cattle grazing in the area. Collected at night down to conifers. Jumping spiders (near the top), Leucauge (small), pholcids near bottom.
22 t (Nuku Hiva) Gillespie and Shapiro hiked down from Mt. Muake. Swept extensively to main road just past conifers (to ~750m). Then collected intermittently on way down mountain on main road, to about 550m). Then walked on to Taiohae.
23 f (Nuku Hiva). Went up Mt. Tekao – R. Gillespie, Jean-Yves Meyer, Frere Maxime, Pascal Villard and Leo Shapiro. Collected from road (1200m) to camp site at ~1185m. Found Tetragnatha right at beginning of trail onwards. Also collected some planthoppers. Collected in proximity of camp site at night.
24 s (Nuku Hiva). From camp site, went towards Mt. Tekao summit. First to one peak, then down valley, then up another peak. Collected on way, and on way back, especially at stream at bottom of valley, elev. 1100m. Then back to camp. Picked up pitfall traps. One ant, LOTS of amphipods and orobatid mites Collected in proximity of camp site at night.
25 s (Nuku Hiva) Picked up camp and left ~7am. Went down to road (raining fairly hard). Jean-Yves Meyer, Leo Shapiro and R. Gillespie went to old road, 1100m. Climbed up hill (to 1130m) and collected up there. Then went along road a bit more, collected along side. Good number of ants. Drove down to Ag station in Tovii. Collected some on way down, by side of road. Stayed night at ag station (~800m).
26 m (Nuku Hiva) Jean-Yves Meyer, Frere Maxime, and R. Gillespie met with officials in Taiohae. L. Shapiro collected on Tovii.
27 t (Nuku Hiva to Atuona) Jean Yves Meyer, Frere Maxime, Jean Pierre, Leo Shapiro, R. Gillespie went to dry forest; collected there. Then to airport for Hiva Oa. Met with george Roderick and Teiki Richmond. T. Richmond drove us up to base of Temetiu trail. Camped there at base of trail.
28 w (Hiva Oa) Roderick and Gillespie hiked up to summit of Temetiu, 1170m. Got there ~1pm. Hiked around ridge trail. Found lots of crab spiders by beating. Also some salticids, not so many Tetragnatha. Camped on ridge, and collected there at night. (Shapiro remained at bottom base of mountain)
29 t (Hiva Oa) Roderick and Gillespie collected along Temetiu Ridge Trail, then hiked back down, collecting on way.
30 f (Hiva Oa) Teiki Richmond picked drove Roderick, Gillespie, and Shapiro to Ootua. Hiked up Ootua (up stream bed, then round side and straight up to top) to 900m. Then looked around summit, and gullies beside it. Found some planthoppers. Roderick and Gillespie hiked down into gully again after dark. Found a few Tetragnatha down there. Lots of pig damage, all through gully and guava.
July
1 s (Hiva Oa) Hiked down from Ootua. Teiki Richmond picked us up at bottom at 7am and drove us back to Atuona. Then he took us in his boat to Tahuata. Were driven up mountain on Tahuata to about 535m. Roderick and Gillespie searched for trail through conifers; unable to go very far due to leg injury that Gillespie had received during descent from Mt. Ootua. Collected at night around camp site at 535m.
2 s (Tahuata) Hiked down mountain on Tahuata. Teiki Richmond took us back to Atuona.
3 m (Hiva Oa) Met Alain LeBronnec and examined library in his house.
4 t (Hiva Oa - Tahiti) To airport and to Nuku Hiva, then to Papeete.
5 w (Moorea) Got ferry over to Moorea. Shapiro and Arnedo went up to 3 Coconuts.
6 t (Tahiti) Roderick, Gillespie and Spagna went over to Tahiti. Met with Jean-Yves Meyer and went with him up Mt. Marau. Stopped at different elevations on Marau: 805m, 870m, 985m, and 1240m. returned to Papeete with Jean-Yves Meyer in afternoon, and picked up Garb, Shapiro, and Arnedo. Drove back up Mt. Marau, camped at 1240m and collected spiders around there at night.
7 f (Tahiti) drove down from Mt. Marau, through Papeete, to Papenoo, then went up Papenoo Valley. Collected by river along valley, at 14km, 195m. Then drove over to Tahiti Iti. Camped by the end of the road, beyond the Belvedere on Tahiti Iti, slope of Mt. Teatara, 650m. Collected there at night.
8 s (Tahiti) Drove back to Papeete. Then to Moorea.
9 s (Moorea)
10 m (Moorea)
11 t (Moorea) Roderick, Shapiro, and Arnedo went up Mouaputa with Victor Wong.
12 w (Raiatea) Gillespie, Roderick, Shapiro, and Arnedo got flight at 10.30am to Raiatea. Hiked up to Temehani Plateau, 800m. Unusual forest there, with lots of hala. Found no Tetragnatha except over stream. Camped on summit.
13 t (Raiatea) Gillespie and Roderick hiked off summit, then got flight back to Papeete. Shapiro, and Arnedo remained and collected on Raiatea.
14 f (Moorea).
15 s Back to USA (Gillespie, Roderick); Shapiro & Arnedo to Bora Bora
16 s Bora Bora – Shapiro & Arnedo
17 m Moorea – Shapiro & Arnedo