Cancer brings forward oviposition in the fly Drosophila melanogaster

Abstract

Hosts often accelerate their reproductive effort in response to a parasitic infection, especially when their chances of future reproduction decrease with time from the onset of the infection. Because malignancies usually reduce survival, and hence potentially the fitness, it is expected that hosts with early cancer could have evolved to adjust their life‐history traits to maximize their immediate reproductive effort. Despite the potential importance of these plastic responses, little attention has been devoted to explore how cancers influence animal reproduction. Here, we use an experimental setup, a colony of genetically modified flies Drosophila melanogaster which develop colorectal cancer in the anterior gut, to show the role of cancer in altering life‐history traits. Specifically, we tested whether females adapt their reproductive strategy in response to harboring cancer. We found that flies with cancer reached the peak period of oviposition significantly earlier (i.e., 2 days) than healthy ones, while no difference in the length and extent of the fecundity peak was observed between the two groups of flies. Such compensatory responses to overcome the fitness‐limiting effect of cancer could explain the persistence of inherited cancer‐causing mutant alleles in the wild.

Cancer adaptations: Atavism, de novo selection, or something in between?

“…genetic, epigenetic, adaptive phenotypic plasticity…) are under strong selection each time a novel malignancy occurs. Each primary tumor originates from a single cell that has to “reinvent the wheel” given that its evolved, malignant, products die with the host , but see the case of transmissible cancers . The highly sophisticated level of organization that coalescent cancer cells achieve in few months or years in tumors within an individual, and laterally between individuals and across species, would be an illustration of convergent evolution – somatic selection operating in environments that are broadly governed by the same ecological constraints (i.e.…”

An interaction between cancer progression and social environment in Drosophila

“…While, at this stage, tumors are not found to affect the survival of flies, previous research suggests that cancer may affect fitness in other ways. Female Drosophila, bearing colorectal tumors, bring forward their peak oviposition period suggesting that flies are adapted to minimize the costs of cancer on fitness (18). The social behavior of cancerous flies found in this study could also be interpreted as an adaptive process, which reduces cancer progression.…”

“…In Drosophila, social isolation leads to a reduced lifespan (23), increased aggression (24)(25)(26), reduced need for sleep (27, 28) and a decrease in the fiber number of the mushroom bodies in the integrative nervous center (29). Furthermore, tumor-like over-proliferation of tissues has been found to occur naturally in Drosophila (30, 31) and induced tumors have also been found to influence fitness traits in individuals (16,18) .…”

“…Sprague-Dawley rats) have demonstrated an association between persistent social isolation and inflammatory responses linked to numerous disease processes, including cancer (9,10,14). Despite cancer (both transmissible and non-transmissible) being an emerging important factor influencing life history traits, even at early stages (15)(16)(17)(18), little is known regarding the reciprocal links between the social environment and the development and progression of this illness. Increasing evidence demonstrates that oncogenic phenomena are extremely prevalent in host populations, and not just in post-reproductive individuals as previously believed (19).…”

Oncogenesis as a Selective Force: Adaptive Evolution in the Face of a Transmissible Cancer

“…Haemic neoplasia in blue mussels ( Mytilus trossulus ) causes reduced phagocytic capacity of haemocytes, leading to reduced immune function and ultimately to increased mortality . Moreover, laboratory experiments showed that Drosophila females with cancer oviposit earlier than healthy ones . The emergence and spread of a transmissible cancer, devil facial tumour disease (DFTD), within Tasmanian devil populations, provides an ideal model system to monitor the long‐term impact of cancer on devil fitness, and to investigate host responses in the evolutionary arms‐race of malignant cells and their hosts.…”