Wednesday, March 4, 2015

Graduate students- employees, scholars, or something in between?

Graduate school has always required that students balance research, classwork, and teaching activities (perhaps with some time for complaining). Though many aspects of graduate school are unchanged, there can be a tension between grad students and their employers driven by a shift in both these groups’ expectations, and the complex nature of STEM graduate school.

This is illustrated well by the current strikes of teaching assistants (primarily graduate students) at University of Toronto and York University – both major Canadian institutions. [And even more extreme cases exist]. The union at U of T has become a defacto union for graduate student issues as well, and the primary sticking point appears to be graduate student stipends, which are far below the poverty line. The students there are striking as teaching assistants (so research work can continue) but their main issue is a holistic “graduate student” issue.

Supposing the components of graduate school have remained similar over the years, why might tension be increasing between what graduate students and faculty/departments expect? Partly because so many other things have changed-–the economy, the workforce, cultural expectations. I think that in the past, it was easier to consider graduate school as a place of passion and intellectual curiosity, where one would make a lousy salary, but consider it “worth it”.  Today, the cost-benefit analysis for getting a PhD is considerably less positive – it takes longer to get a PhD, on average, and the payoff in terms of obtaining a faculty or other job, makes this less clear. The cost of education, particularly in the US, is immense: the possibility of student loan debt from 4-8 years of postgraduate education is fairly unpalatable.

From Nature.
As the realities change, so too do the expectations. That on its own would be the source of some tension. But the dual nature of graduate school compounds the tensions since it is difficult for graduate students, faculty, and department heads to evaluate what reasonable expectations are for things such as pay, hours, vacation time. For most students, graduate school has aspects of both a clear job (usually teaching duties—running labs, marking tests and assignments, sometimes lecture duties) and a clear studentship (class work, appraisal exams, all culminating in a defense). It also includes research, done in a lab or the field, which may vary between being a job (doing tasks primarily for the PI, monitoring undergrads, ordering supplies) and an intense learning experience. Employment involves contracts with expectations and restrictions, set hours and wages; being a student lacks the same expectations but is often associated with greater freedom and personal growth. The extent to which faculty and graduate students see the position as “student” or as “job” may well differ.

The interaction of economic realities with the duality of graduate school is an important issue. Should graduate school be considered the start of one's working life? If so, is it equivalent to an entry-level position? After all, TAs do a lot of grunt work -- marking, marking, and more marking, run simple labs and tutoring sessions -- and many universities hire undergraduates to do similar tasks. On the other hand, graduate students are also high-achievers doing complicated analyses for research, and have reasonably high education levels. Graduate school may come with opportunity costs  - peers with similar educations tend to have jobs and retirement funds. In contrast, the pure academic path usually means you will live frugally for many years before your first "real" position (and you may be in your 30s or later before you get it).

There may be some generational changes as well. It is suggested that Millenials/Generation Y have different priorities than previous generations: they strongly desire fulfilment from their work, but also competitive compensation and job flexibility (e.g.). The downsides of graduate school are greater and perhaps more obvious to this generation: if it is a job, it is poorly paid and entry-level, if it is a studentship, it comes with an opportunity cost. But how to evaluate it when it is both? It is undeniably easier to go through graduate school for those who don't have to deal with the dualities - such as through having a fellowship that allows a student to do research and classes only. Most people are still in graduate school for the same reasons as they always have been - love of science and learning. That hasn't changed. But the meaning of graduate school itself may well have changed. There is no one or easy solution to the issue. But no doubt a recognition by both sides of the realities of being a graduate student (and a supervisor) and honest communication about expectations on both sides (and sometimes, perhaps a little pressure) would go far. 

The real truth about graduate school according to the Simpsons...

**I just want to note that this is inspired by--but not addressing--the U of Toronto situation, and any comments that simply want to debate specific circumstances in particular universities will be deleted...
Larger discussion of the general issue always welcome.

Friday, February 27, 2015

Going natural: biological control of insect pests

*Guest post by Sheena Fry

Damage caused by agriculture pests is one of the most important factors of crop yield reduction (Cramer, 1967; Oerke et al., 1994) and can cause billions of dollars worth of damage each year (e.g. in Brazil, insect pests cause up to US$ 17.7 billon year-1 of damage, Oliveira et al., 2014). Due to its economic impact, controlling pest populations is a priority for agricultural scientists. Chemical control is the primary method of pest management due to its relatively low costs and high effectiveness (Cooper and Dobson, 2007). Despite the widespread use of chemical controls, the health and environmental risks associated with their use are well known (Pimentel et al. 1992; Pimentel, 2005). The risks associated with pesticide use, as well as the evolution of pesticide resistance, has lead to a surge in interest in the use of biological control for pest management over the past 50 years.

The most important decision to be made in a biological control program is which biological control agent to use against a pest. Success rates for biological control of insects are low, with only 24-35% resulting in the establishment of the introduced species (Hall and Ehler 1979, van Lentern, 1983) and only 16% resulting in complete control of pest species (Hall et al., 1980). What determines the success of colonization and establishment is a key question in biological control research and must be answered in order to make predictions about establishment and success of introduced species. In 1965, Debach attempted to identify characteristics of successful colonizers but found that neither success nor failure could be explained by the presence or absence of a common characteristic. Over the past 50 years, several attempts have been made to list characteristics of successful invaders (e.g. Murdoch et al., 1985) and while they seem logical, there are too many exceptions for them to be used as a reliable indicator of a species’ potential to colonize and establish in a new area. DeBach saw “no possibility of predicting the fate of a purposely colonized imported entomophagous insect” and at present it remains an elusive goal (Fischbein and Corley, 2015).
Paul Debach 1914-1992

The environmental and health risks associated with chemical controls of insects (see references above) are not an issue when using biological controls. In addition to this, successfully established biological control species will be able to maintain stable populations without the need for additional investment by humans (unlike chemical controls, which must be applied each season). Despite the obvious benefits of biological control, there are also risks associated with the use of insects in biological control, such as the risk to non-targeted species (Simberloff and Stiling, 1996) or host switching. In order to make decisions about biological control we need to understand the evolution of introduced species in new environments, which can increase the efficiency of biological control (through post-colonization adaptation) or can increase the risk to non-targeted species. “The Genetics of Colonizing Species” (1965) brought together evolutionary biologists and ecologists (theoretical and applied) to discuss the evolution of introduced species. In DeBach’s chapter, he focused on colonizing entomophagous insects and, using biological control case studies, looked at the relative influence of pre- and post colonization adaptation, a key question in evolutionary biology. One such case study was the introduction of a parasitoid wasp (Comperiella bifasciata Howard, Figure 1), which was introduced to control a citrus pest, the California red scale (Aonidiella aurantii Maskell). The parasitoid wasp was released throughout southern California but initially was only able to establish at one location. It slowly spread and increased in abundance and, by 1957 was found at various locations throughout southern California. DeBach interpreted the poor initial establishment of the parasite followed by intense colonization as an indication that genetic adaptation had occurred.

Figure 1. A female parasitic wasp (Comperiella bifasciata Howard) infesting a California red scale (Aonidiella aurantii Maskell), from Forester et al. (1995).

Fifty years have passed since the publication of “The Genetics of Colonizing Species” (1965) and understanding the relative effects of pre- and post-colonization adaptation has remained an important issue. Phillips and colleagues (2008) examined the relative effects of genetic drift and selection in the frequencies of two asexually reproducing, genetically distinct parasitoid biotypes. This South American parasitoid wasp (Micrictonus hyperidae Loan, Figure 2) was introduced as a biological control for a pasture pest (Listronotus bonariensis Kuschel, Figure 2) in New Zealand in 1992. Phillips and colleagues recorded the relative frequencies of each biotype over a 10-year period and found that changes in biotype frequency were consistent with strong directional selection, favouring one of the parasitoid biotypes. This resulted in parasitoid populations being better adapted to New Zealand conditions than those originally released. 

Figure 2. A female parasitic wasp (Micrictonus hyperidae Loan, right) infesting a South American weevil (Listronotus bonariensis Kuschel, left). © Copyright AgResearch

There have been significant advance in the tools (statistical and molecular) available for the study of post-colonization success and adaptation since the publication of “The Genetics of Colonizing Species” (1965). These tools allow for better understanding of the post-colonization process of introduced species but, despite these advances, there has been little progress towards being able to predict the success of introduced species.

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