Aufgabe 1 - Teilaufgabe 2: Stammbäume, Verhalten… · Abitur NRW Biologie GK · Haupttermin · bilingual Englisch 2023

Material A: The Genus Ariamnes on the Hawaii Archipelago

The genus Ariamnes belongs to the family of tangle-web spiders 1 and occurs with numerous species on the Hawaii Archipelago. The biggest species, A. kahili, reaches a maximum size of 11.3 mm. Ariamnes spiders hide in various resting habitats during daytime (Table 1). They are nocturnal predators that do not build site-specific webs. Instead, they run around looking for prey and catch them with a web woven between their hind legs. A kleptoparasitic behaviour was observed in some species: these spiders climb onto the webs of other spider species and feed on their prey or on the spiders themselves. Other spider species and especially birds feed on Ariamnes spiders.

Table 1 Occurrence and selected traits of the known Ariamnes species on the Hawaii Archipelago

Species · Habitat · Resting habitat during daytime · Shape of the abdomen · Colouring · Kleptoparasitic behaviour

A. huinakolu · humid forest · moss · short · dark · shown

A. kahili · humid forest · under leaves · long · gold · shown

A. uwepa · moderate humidity · under leaves · long · gold · not shown

A. makue · moderate humidity · dead ferns · long · dark · shown

A. poele · humid forest · dead ferns · long · dark · not shown

A. melekalikimaka · humid forest · under leaves · medium · gold · shown

A. alepeleke · humid forest · under leaves · medium · gold · not shown

A. laau · humid forest · dead ferns · long · dark · shown

A. corniger · dry forest · white lichens · long · matt white · not shown

A. waikula · humid forest · under leaves · long · gold · not shown

A. hiwa · humid forest · cracks in rocks · long · dark · not shown

1 Haubennetzspinne

Material B: Relationships between Ariamnes Spiders

The Hawaii Archipelago is located in the Pacific Ocean 3800 km from the North American continent and is of volcanic origin. Among the islands in the Archipelago, Hawaii is the biggest and youngest, and Kauai is the oldest (Figure 1). The islands offer a wide range of habitats for a large number of animal and plant species.

Mitochondrial and nuclear DNA sequences were used to analyse the relationships between the Ariamnes spiders of the Hawaii Archipelago and to construct a phylogenetic tree (Figure 2). Information about the current distribution of the described Ariamnes species was added to this phylogenetic tree. The spider species Argyrodes trigonum, which occurs in the USA, is coloured yellow-brown and shows kleptoparasitic behaviour.

Aufgabenstellung: Topic: Evolution of Ariamnes Spiders

2. Name the methodological steps required to build the phylogenetic tree shown in Figure 2 (Material B). Analyse the phylogenetic relationships, considering how the islands of the Hawaiian archipelago were colonised (Material B). Illustrate two ways in which Ariamnes spiders could have colonised the new islands (Materials A and B). [22 Punkte]

a)

b)

c)