Rattan litter-collecting structures attract nest-building and defending ants

Abstract

Rattan is an important climbing palm taxon in Malaysian tropical rain forests. Many rattan species have unique structures directly associated with certain ant species. In this study, four rattan species (Daemonorops lewisiana, Calamus castaneus, Daemonorops geniculata and Korthalsia scortechinii) were inspected and documented in a field survey concerning their relationships with several ant species. We noticed that two rattan species (D. lewisiana and C. castaneus) were more likely to be associated with ants compared to their neighbouring rattan (Plectomia griffithii). However, D. lewisiana and C. castaneus did not directly provide shelters for ant colonies, but possessed unique structures: upward-pointing spines and funnel-shaped leaves, which are equipped to collect more litter than P. griffithii. To test our litter collecting hypothesis, we measured the inclination of spines from the stem. Our results showed the presence of ant colonies in the litter-collecting rattans (D. lewisiana and C. castaneus), which was significantly higher compared to a non-litter-collecting rattan (P. griffithii). We propose a complex and novel type of adaptation (litter-collection and provision of nesting materials) for rattans, which promotes interactions between the rattan and ants through the arrangements of leaves, leaflets, and spines. In return, the rattan may benefit from ants' services, such as protection, nutrient enhancement, and pollination.

Joint effect of human papillomavirus exposure, smoking and alcohol on risk of oral squamous cell carcinoma

“…Alternatively, others observed an increased risk of oropharyngeal cancer in patients who were seropositive for anti-HPV16 antibodies and had tobacco exposure [15,25,26]. Other studies of the interactions among tobacco and alcohol use and HPV16 infection demonstrated no evidence of synergistic interactions [10,[24][25][26][27][28][29]. In the present study, we observed a strong combined effect of HPV16 seropositivity with tobacco or alcohol use on risk of oral cancer, particularly for oropharyngeal cancer.…”

“…HPV markers can be detected as HPV DNA in exfoliated oral cells and biopsy specimens and as anti-HPV antibodies in serum. Smith et al examined HPV DNA in exfoliated oral cells and found that detection of HPV DNA in them was associated with increased risk of oral cancer [16], whereas Herrero et al found no association between HPV DNA in exfoliated cells and detection of HPV DNA in oral tumor biopsy specimens [27]. Other studies support the ndings described by Herrero and colleagues, suggesting that HPV DNA in exfoliated cells is a poor marker of tumor HPV status [15].…”

“…Also, small sample sizes may also limit the statistical power of data analysis, which could restrict the generalizability of the ndings. Furthermore, although the use of HPV serology enabled us to use a cancer-free control group, HPV serology we used is not speci c to oral cancer tumor status but is rather a reasonable indication of HPV exposure [27,30]. Infection with high-risk HPV types other than HPV16 may also be associated with oral cancer, but we limited this study to anti-HPV16 antibodies.…”

Rattan spines as deterrence? A spinescence study on different species of rattans

“…The up-pointing spines were found to collect litter and debris, and this structure may help encourage colonization of defensive ants for protection from herbivory . 30 The strength of the spines is crucial in playing defensive roles as well. The stronger the spines, the tougher they are and more resilient toward herbivores.…”

“…Rattan spines may also deploy various roles besides defense. According to 30 , the rattans D. lewisiana and C. castaneus collect leaf litters from canopy level with the help of their up-pointing spines and the litter thus accumulated on their stem may form a nutrient trap and it also serves as a suitable environment for ant colonies. Ants on those rattans may enhance the nutrient content for the rattan and also protect the rattan plants from herbivores.…”