Bioacoustics of Phaeophilacris (Taenacris) kereita

Ecological remarks— Kereita cave is located within the limits of the Gatamaiyu Forest Natural Reserve. Gatamaiyu Forest ( Fig. 18 ) is a remaining section of the Kikuyu Escarpment Forest, encompassing a vast area of 37,620 hectares. This expansive forested landscape comprises several distinct forest blocks, including Kereita, Kinale, Kamae, Kieni, Raggia, Kijabe, and Uplands, in addition to Gatamaiyu. Within Gatamaiyu Forest, which spans 4,720 hectares, approximately 75% consists of native forest, while 8% is characterized by exotic tree species. The remaining portion features scrublands, bamboo groves, and herbaceous croplands. Despite extensive logging activities occurring in the 1950s and 1960s, Gatamaiyu Forest has remarkably regenerated over time. This forest serves a vital role as a watershed area for numerous rivers and springs, including the Gatamaiyu, Bathi, Kiruiru, and Nyanduma rivers. The entrance to Kereita Cave is situated at an altitude of 2,400 meters above sea level, nestled in the heart of the forest, adjacent to a substantial waterfall ( Fig. 19 ). Due to its proximity to the lake created by the waterfall, it is likely that during periods of heavy rainfall, the lower main chamber of the cave may experience flooding. Nevertheless, the cave floor in the main chamber is consistently damp due to the mist generated by the waterfall, which permeates through the cave entrance. The cave consists of a main chamber, approximately 20 meters in length, and a secondary upper conduit, spanning approximately 10 meters. Notably, individuals of the species Phaeophilacris ( T. ) kereita n. sp. were not observed within the lower main cave chamber. Instead, they were primarily found in the lateral upper conduit, particularly along the cave’s ceiling and walls. These specimens tended to cluster around cracks in the rock formations ( Fig. 21 ). It is worth mentioning that the majority of the specimens observed in these aggregations were immatures, with only two adult males identified ( Fig. 22 ), despite the presence of several sub-adult male specimens. The primary organic materials present in the cave included plant debris carried in by water and bat guano. An intriguing aspect of the cave environment is the intense noise level caused by the nearby waterfall. The noise is so pronounced that even holding conversations inside the cave becomes challenging.Consequently, any form of acoustic communication by the crickets is impeded. The behavior of these specimens was particularly intriguing. Typically, cave crickets tend to exhibit evasive behavior, scurrying away when approached with headlamps, suggesting a degree of photophobia and a tendency to seek shelter when disturbed. However, what sets Phaeophilacris ( T. ) kereita n. sp. apart is the surprising composure of these specimens: they remained remarkably calm, even in the presence of a human with powerful lights in close proximity. Unlike other species, they did not display any attempts to seek shelter but rather remained still and composed. Although the waterfall near Kereita Cave is a tourist attraction, the cave itself appears to receive very few visitors. To access the cave, one must cross the river, as its entrance is on the opposite bank from the trail. Additionally, because the cave entrance is in close proximity to the waterfall, many visitors seem hesitant to enter, often choosing to avoid it. As a result, the interior of the cave remains relatively undisturbed, showing minimal signs of human interference. Furthermore, access to the cave is only permitted when visitors are accompanied by park rangers, as the area is known to have elephants and other wildlife that could pose a risk to humans.