Gone with the rain: negative effects of rainfall on male reproductive success in a nest-building arachnid

33 ROJAS VALLE, A. Gone with the rain: negative effects of rainfall on male reproductive 34 success in a nest-building arachnid. 2018. Dissertação (Mestrado) – Instituto de Biociências, 35 Universidade de São Paulo, SP. 36 37 In nest-building species, offspring survival and reproductive success of parental individuals 38 are strongly influenced by nest location and quality. Thus, quantifying the influence of 39 abiotic conditions on nest integrity is important to predict the effects that weather variability 40 may have on offspring survival and parental reproductive success. Here we investigated 41 how rainfall affects nest integrity and how nest integrity influences male attractiveness and 42 nest tenure. Our study species was the harvestman Quindina limbata, in which males build 43 cup-like mud nests on fallen logs and protect the eggs against predators and fungi 44 infestation. Our dataset is based on 12 months of regular inspections of over 150 nests in a 45 tropical rainforest from Costa Rica. We found that 43% of the nests were destroyed by 46 rainfall. The drag force promoted by rainfall running on the log surface negatively affected 47 nest integrity by decreasing the wall perimeter and the floor area. The intensity of fungi 48 cover was not explained by nest position or by precipitation. No matter the body size of the 49 owner males, nests with high integrity received more eggs than nests with low integrity. 50 Curiously, nests with high values of fungi cover received more eggs. Finally, nest integrity 51 and fungi cover did not affect nest tenure, but the probability of males abandoning their 52 nests increased with time they did not receive eggs. Considering that intense rainfall occurs 53 all year long in tropical forests, the best males can do to decrease the chances of nest 54 destruction is to select protected places to build their nests. Protected sites may keep nest 55 structure better preserved, improve offspring survival, attract more females, and ultimately 56 increase male reproductive success. 57 Key-words: abiotic conditions, extended phenotype, fungi, harvestman, male attractiveness, 58 mating success, nest abandonment, nest integrity, paternal care. 59 Gone with the rain: negative effects of rainfall on male reproductive 60 success in a nest-building arachnid* 61 62 Andrés V. Rojas a,b,c, Diego Solano-Brenes b, Danilo G. Muniz d and Glauco Machado d 63 a Programa de Pós-graduação em Ecologia, Instituto de Biociências, Universidade de São Paulo, Rua 64 do Matão, trav. 14, no. 321, São Paulo, SP, 05508-090, Brazil. 65 b Escuela de Biología, Universidad de Costa Rica, Sede Rodrigo Facio, San Pedro de Montes de Oca, 66 2060 San José, Costa Rica. 67 c Veragua Foundation for Rainforest Research, Las Brisas, Río Blanco, Limón, Costa Rica. 68 d LAGE do Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, Rua do 69 Matão, trav. 14, no. 321, São Paulo, SP, 05508-090, Brazil. 70 Corresponding author. E-mail: andresrova@gmail.com 71 * Este manuscrito foi redigido de acordo com as regras de formatação da revista Oikos, para onde pretendemos submeter o trabalho após a defesa.