This doctoral thesis, directed by David Martínez, analyzes the temporal and spatial expression patterns of some genes involved in light regulation of the aphid life cycle. Part of the results of the thesis have been published in the Journal of Insect Physiology. The thesis was defended on March 10, 2021.

Acyrthosiphon pisum is a highly seasonal species of aphid. During the favorable season, only viviparous parthenogenetic females are produced. In autumn, when there is less light (shorter photoperiod), A. pisum perceives the difference and these females give birth to males and then oviparous sexed females. These will lay eggs that resist the winter and hatch in spring, restarting the cycle. Some mutants do not respond to photoperiod and reproduce asexually throughout the year. The molecular mechanisms of the transition to sexual reproduction are unknown, as are the molecules involved in detecting the length of the day – the photoperiodic photoreceptor. The objective of this thesis was to investigate the mechanisms and genes involved in the photoperiodic response in aphids, with a special interest in photosensitivity by studying the genes of the opsin and cryptochrome families (cry1 and cry2). Differential gene expression was compared in aphids exposed to short days that induce the production of sexualized males and females. Some of the genes with altered expression are related to the synthesis of hormones, neuropeptides and neurotransmitters. Other regulated pathways are involved with light perception, brain remodeling, as well as the production of sexualized females. The repertoire of seven opsin genes and cry1 were characterized as candidates for participating in photoreception and their spatial expression patterns were studied in various insect tissues. The results of this thesis illuminate key aspects of the photoperiodic response in aphids.
Jorge Mariano Collantes' doctoral thesis has been developed in the Evolutionary Genetics group of the I2SysBio under the supervision of David Martínez (Full Professor of Genetics, Universitat de València). During the development of the thesis, Jorge Mariano Collantes has been the beneficiary of a contract from the FPI Research Personnel Training program of the Ministry of Science and Innovation. The panel was made up of Francisco J. Silva (Universitat de València), Teresa Cortés (London School of Hygiene & Tropical Medicine) and David Doležel (Institute of Entomology, Biology Center CAS), who rated the thesis as outstanding.