Abstract

         This review will discuss the effects of climatic changes on genetic variability in multiple species including insects and plants. It is the process of hybridization where subspecies reproduce amongst each other. This usually occurs when there is an overlap between two different populations. These overlapping situations are caused by climatic changes. However, it is crucial to consider that the growth in plants is distinct from the growth of an animal which produce contrasting results when being studied. Overall, the species within these studies undergo endangerment as well as a decrease in genetic variability.

Climate Change and Organisms

As climate continues to rise across the Earth, it also continues to affect the environment. Gradually progressing into more severe conditions since not enough efforts are made to put a halt to this issue. Many organisms are struggling to thrive under these conditions. Therefore, to survive and preserve their existence for future generations it has been seen that organisms hybridize. Hybridization is the process in which two distinct species of organisms combine in reproduction, producing a mix of both species. It is crucial to study these frequent processes occurring in several species since it demotes genetic variability. Not only that but it advances the endangerment of the species participating in these processes. This review will capture the effect climate change exudes on the cross-reproduction in animals and plants as well. The review will include analysis of the similarities in studies done on insects, a contrast in methods of the study done on plants and insects, and lastly a comparison between the results of all the studies. Current research indicates that climate change is the reason there have been crossovers in multiple species which in the long run reduce genetic diversity.

Hybridization Processes within Two Different Insect Species

         Hybridization is not new. It has been an action known to organisms to reproduce and maintain their species alive whenever there has been a decrease in populations. With a rise of severe climatic changes throughout the world, there has been a rapid decrease of many species as well. Furthermore, as the populations of some organisms begin to dwindle hybridization is triggered amongst multiple organisms to maintain their survival. It is an ongoing issue in the environment as climate change continues to spiral out of control. Argus butterflies and Damselflies were the subjects of study. Both insects were studied with the same intentions of identifying the role of hybridization in a setting where climatic changes was the threat. In argus butterflies it was determined that these species already underwent through hybridization, prior to the current hybridization, which leads to a minor genetic difference between northern argus butterflies and southern argus butterflies (Mallet J et. al, 2011). These subjects differentiate from the damselflies since they are species that are individual from each other. Not once have they crossbred which leaves room for more accurate and significant results rather than the butterflies. The damselflies have original genetics and are completely different from another subspecies of damselflies. Therefore, it must be a normal interaction for northern and southern argus butterflies to interbreed since they have done so in the past, prior to climate change. Increasing climatic changes pushed these two subspecies of butterflies to interbreed again. In damselflies, about forty subspecies were prone to be affected by the rising climatic changes as well as to have their genetic composure diminished (Nava-Bolanos A et. al, 2019). Climate change has disrupted migration patterns for these species which is what has caused an overlap in certain areas where they live. Overlapping environments is what primarily causes interbreeding in subspecies that had never met. Climate change poses a threat to damselflies and argus butterflies’ genetic variation. Considering the northern and southern argus butterflies are related, it poses a much higher risk for their genetic make-up. The few differences these two subspecies have could be extinguished. Implying that a subspecies of argus butterflies will go extinct if climate change continues to occur. Damselflies had a larger sample population which offered more representation than argus butterflies, encouraging stronger outcomes. 97 pairs of the species were found at higher risk of intertwining with each other due to the probability of sharing the same habitat (Nava-Bolanos A et. al, 2019).

Plants and Animals Undergoing Hybridization due to Climate Change

Differences in Methods

         Plants are also organisms that are affected by climatic changes as much as animals are. Two Eucalyptus plants, E. risdonii and E. amygdalina, were grown separately using two different genome sequences for each plant (Pfeilsticker TR et. al, 2022). A different method had to be used to administer the effect an admixture of genetics would pose on the development of the Eucalyptus plant. Similarly, to the argus butterfly analysis, there were two subspecies of Eucalyptus used as subjects for the experiment to make a comparison. However, this experiment had to be conducted on a long-term span. The Eucalyptus plants had to be grown from seed since it is from the starting point where manipulations can be made for the growth or changes in the plant. The studies from the insects seemed to be more of an observational study where samples of subjects are taken randomly from an already existing population. Unlike with the Eucalyptus where it started from scratch since genetic sequences had to be altered to stimulate a change. The Eucalyptus captures how hybridization affects the development of the organism and analyzed how climate change produced these effects. It is acknowledged that climate change consistently has threatened various Eucalyptus species throughout series of droughts, excessive rainfalls, and even wildfires. These events give different ways for Eucalyptus to thrive which in some cases can lead to an admixture of species. This has mostly been seen in animals such as Damselflies and the argus butterflies. However, not only were the genetic sequences modified in the Eucalyptus, but there were also plenty of weather modifications for each family tree which were placed in different groups. In each group, the families experienced different changes in climate (Pfeilsticker TR et. al, 2022). Therefore, two variables are manipulated to reinforce changes in the development of a Eucalyptus plant. The study contained artificially made and natural plants. The analysis over the insects could not have controlled weather conditions the way it was done with the Eucalyptus plant. Therefore, the insects have a much more natural response to the changes of their surroundings. Whereas the Eucalyptus had plenty of intentional changes within its surroundings for a change in its development. Given the different conditions each plant was placed allows more insights to be done on each individual group of plants since it can produce different reactions or effects towards the plant.

Development of Plants and Animals due to Climatic Changes

         Climate change continues to be an issue in modern society which continues to pose a threat to many species. It is mostly seen through the destruction of habitats due to natural disasters. However, climate change is also responsible for misdirecting certain species’ migration patterns or even their distribution patterns as well. 125 species of Damselflies were found to have separate distribution areas, however, 310 species demonstrated they had overlapping distribution areas due to current climatic changes (Nava-Bolanos A et. al, 2019). Although there are some species that are not at risk of coexisting with other species, there is still a much higher number of species that are at risk on interbreeding and losing their distinctiveness. Overlapping ecosystems decreases genetic variation in subspecies within the same specie which can endanger one another (Mallet J et. al, 2011; Nava Bolanos A et. al, 2019). Brown argus butterflies began to crossbreed due to the overlapping habitat they have repossessed. Climatic changes have driven southern argus butterflies to migrate to the north which is where the northern brown argus butterflies are found. Both are different subspecies. Eucalyptus plants were monitored and consistently had changes made within their environment to enact climate change as well as an overlapping of genetics. Not only that but this study ranged from the years 1990-2019 which allowed for the entire growth of Eucalyptus plants, E. risdonii and E. amygdalina, to be analyzed. A longer span allows researchers to directly encounter significant changes being produced in the development of the plant. 71% of hybrids, 75% pure E. amygdalina and 100% of pure E. risdonii survived since 1990 (Pfeilsticker TR et. al, 2019).

         Modern research demonstrates that climatic changes pose a threat to the individuality each species of organisms withhold genetically. As organisms continue to overlap, their chance of losing genetic variability rises, which furthermore endangers subspecies. Admixtures of genetics also affects the ability for an organism to thrive. Future research may include looking into different methods that can be done to avoid having more species interbreed with each other. Different theories can be tested as well regarding genetics found in organisms, or other variables other than climate change can be tested.

References

Mallet J, Wynne IR, Thomas CD. August 2011. Hybridization and climate change: brown argus butterflies in Britain (Polyommatus subgenus Aricia). Insect Conserv Divers. 4 (3): 192-199. [Accessed: 16 April 2024].

Nava-Bolanos A, Sanchez-Guillen RA, Wellenreuther M, Munoz J, Torres-Pachon M,Novelo-Gutierrez R, Cordoba-Aguilar A, Hassall C, Keyghobadi N. September 2019. Predicting hybridization as a consequences of climate change in damselflies. Insect Conserv Divers. 12 (5): 427-436. [Accessed: 16 April 2024].  

Pfeilsticker TR, Jones RC, Steane DA, Harrison PA, Vaillancourt RE, Potts BM. January 2022. Expansion of the rare Eucalyptus risdonii under climate change through hybridization with a closely related species despite hybrid inferiority. Ann Bot-London. 129 (1): 1-14. [Accessed: 16 April 2024].