The life cycle ofGregarina cuneatain the midgut ofTribolium castaneumand the effects of parasitism on the development of insects

Abstract

Tribolium castaneum Herbst 1797 (Coleoptera: Tenebrionidae), an important pest of stored grains and byproducts, is naturally infected by Gregarina cuneata Stein 1848 (Apicomplexa: Gregarinidae). Changes in the life cycle of insects caused by the parasite development in the midgut were studied. Trophozoites, gamonts (solitary and associated), and gametocysts were present in the midgut of the insects. In young trophozoites, the apical region differentiated into an epimerite that firmly attached the parasite to the host epithelial cells. With maturation, trophozoites developed in gamonts that were associated with the initiation of sexual reproduction in the cell cycle, culminating in the formation of the spherical gametocyst. Morpho-functional analyses indicated that gregarines absorb nutrients from infected cells and can occlude the midgut as they develop. Consequently, nutritional depletion may interfere with the host's physiology, causing decreased growth, delayed development, and high mortality rates of the parasitized insects. These results suggest G. cuneata could be an important biological agent for controlling T. castaneum in integrated pest management programs.

Transcriptional responses to short‐term and long‐term host plant experience and parasite load in an oligophagous beetle

“…Likewise, a gregarine prevalence of 91% was found in field‐collected beetles of Tribolium castaneum (Tate & Graham, ). In this beetle, gregarine infection can drastically increase mortality, likely due to the nutrient depletion caused by the parasite (Gigliolli et al., ). In Phaedon brassicae populations, infection rates of 100% were found (Kim, Min, Kwon, Choi, & Lee, ).…”

“…The insect's ability to utilize plant nutrients and to detoxify allelochemicals may be enhanced or diminished by symbiotic or parasitic microorganisms occurring in the gut (Engel & Moran, ; Welte et al., ). Gut microbiota may assist in digesting and supplementing a low‐quality diet (Scully et al., ) but could also have detrimental effects caused by nutrient depletion (Gigliolli, Julio, & Conte, ). Moreover, the composition of gut microbiota affects the immune responses of herbivores (Tate & Graham, ).…”

Gregarines modulate insect responses to sublethal insecticide residues

“…They can lead to a delayed development, higher mortality, and reduced reproduction of their hosts (Zuk 1987a ; Córdoba-Aguilar et al 2003 ). Nutrient deprivation induced by the gregarines may be causing some of these negative effects (Gigliolli et al 2016 ). However, gregarine infections can also be benign for their hosts (Harry 1967 ; Kim et al 2014 ) or even beneficial, for example, by accelerating the development or lowering predation (Alarcón et al 2017 ; Soghigian et al 2017 ).…”

Friend or foe? The apparent benefits of gregarine (Apicomplexa: Sporozoa) infection in the European earwig

“…Over the last decades, a large number of studies showed that the presence of gregarines typically comes with a broad range of costs for the hosts. For instance, gregarine infection reduces body weight and food consumption in the grasshopper Atractomorpha crenula (Johny et al, 2000), increases susceptibility to a fungal pathogen in the cockroach Blattella germanica (Lopes and Alves, 2005) and hampers larval and pupal development in the mosquito Aedes triseriatus (Beier, 1983) and the red flour beetle Tribolium castaneum (Gigliolli et al, 2016). In several damselfly species, the presence of gregarines also alters survival, egg production, mating decisions, oviposition strategies and wing ornaments (Córdoba-Aguilar et al, 2003;Córdoba-Aguilar and Munguía-Steyer, 2013;Suhonen et al, 2017), while it reduces the capability of male odonates to defend their territory (Siva-Jothy and Plaistow, 1999).…”