Browsing by Autor "Daniela Madrigal-Tejada"

Now showing 1 - 2 of 2

Antlion allometry suggests a greater importance of prey capture among first larval instars
(Taylor & Francis, 2021) Alejandro G. Farji‐Brener; Agostina S. Juncosa‐Polzella; Daniela Madrigal-Tejada; Diego Centeno‐Alvarado; Mariana Hernández‐Soto; Mayori Soto‐Huaira; Sebastián Gutiérrez‐Cruz
First larval stages require adequate feeding to reach subsequent instars. However, the accumulation of reserves is also important in the last larval instar because it is vital to pupate and successfully perform metamorphosis into adulthood. We indirectly determined the presence of changes in the relative importance of prey capture through larval ontogeny in the antlion larvae (Neuroptera Myrmeleontidae), a sit-and-wait predator with three instar stages that capture preys that fall into their pit-traps. We used scaling relationships between the size of body parts directly related to prey capture (prothorax) versus those that are not (thorax + abdomen). The prothorax (neck, head, and mandibles) is used in the pit building, prey capture, and re-capture, and pit cleaning. We measured the body parts of 70 larvae of Myrmeleon crudelis in a tropical rain forest of Costa Rica. The prothorax showed negative allometry: it was proportionally larger in the first than in the last instars. These results support the growth hypothesis, which states that food acquisition is key in the earlier stages of larval development. First instars can be more food-limited than later instars because they build small pit-traps where only very small arthropods can fall; have smaller mandibles and relatively lower grab force, increasing the probability of the prey escaping; and have smaller fat reserves and thus, are unable to resist long periods of starvation. This illustrates the relevance of using scaling relationships to better understand how ecological pressures change along ontogeny, emphasizing the role of food acquisition at earlier ontogenetic stages
Disadvantages of living in a populous neighborhood for sit‐and‐wait predators: Competition for space reduces pit‐trap size in antlion larvae
(Wiley, 2020) Alejandro G. Farji‐Brener; Agostina S. Juncosa‐Polzella; Daniela Madrigal-Tejada; Diego Centeno‐Alvarado; Mariana Hernández‐Soto; Mayori Soto‐Huaira; Sebastián Gutiérrez‐Cruz
Abstract The study of how trap design responds to biotic and abiotic conditions can help to understand the selective forces affecting the foraging of trap‐building organisms. We experimentally tested whether pit design can be modified by intraspecific competition for space in larvae of Myrmeleon crudelis , a common sit‐and‐wait predator that digs conical pit traps in the soil to capture walking arthropods. In a tropical forest in Costa Rica, we measured pit dimensions, larval body size, and the level of competition (i.e., density of neighboring traps) in 40 antlion larvae. These larvae were then taken to the laboratory and allowed to build new traps in individual containers. We measured within‐individual changes in the size of traps in the field and in the laboratory, and related these to the level of competition experienced in the field. Larvae with relatively high levels of competition in the field showed a greater increase in the size of their pits in the laboratory. This change was independent of larval size. Larvae with none or few neighbors in the field showed little change in their pit sizes, whereas those with higher competition levels increased their diameter and depth up to 1,400% and 1,000%, respectively. Our results demonstrate that, at least in high‐density aggregations, pit design is restricted by competition in addition to the constraints imposed by body size. This work suggests that biotic interactions can play a role in the design of extended phenotypes in sit‐and‐wait predators that live in dense aggregations.