Water hyacinth is the target of nine biological control agents in South Africa including Neochetina eichhorniae (Warner) and Neochetina bruchi (Hustache) (Coleoptera: Curculionidae). These two weevils have also been released against water hyacinth in Rwanda, but failed to control the weed invasion, possibly due to high turbidity in the country's water bodies. This study therefore aimed to investigate the effect of water turbidity on the establishment and performance of N. eichhorniae in Rwanda. Turbidity levels were measured over two seasons in four Rwandan rivers and two lakes. The results were then used to benchmark laboratory trials to test the effect of turbidity on the weevils' development. Water hyacinth plants were maintained at fours turbidity levels: Clear water (2 Nephelometric Turbidity Units (NTU): low (85 NTU), medium (600 NTU) and high (1500 NTU). Each treatment plant was inoculated with three N. eichhorniae larvae, while control plants were free of larvae. Plant growth was measured weekly for three months, while adult weevil emergence was recorded from the 56th day of the experiment. The number of adults emerging from the treatment plants grown in the clear water, low, medium and high turbidity levels were 24, 21, 12 and 0, respectively. Larval feeding was greater on plants growing in clear water and the low turbidity, compared to the medium and high turbidity treatments. These results indicate that N. eichhorniae may not establish or perform well in water bodies with high levels of turbidity, which in turn enhances the growth of water hyacinth, allowing compensatory growth for weevil feeding.

This study explored the Rwandan secondary students’ opinions on learning biochemistry concepts covered in the Rwandan advanced level of secondary school biology curriculum, and the reasons behind the difficulty of the concepts. In this research, sequential exploratory mixed-method designs were adopted. The sample comprised 195 secondary school students, who were purposively selected from the schools in Rwamagana and Kayonza districts of Rwandan Eastern Province. Data were collected using self-administered questionnaires and focus group semi-structured interview guides. Data analysis was carried out using both quantitative and qualitative approaches. Results from this research showed that photosynthesis and respiration are the major units that are challenging to study with the respective percentages of 62.5 and 75.1. On the other hand, the concept of enzymes is the most difficult according to students’ views. The lack of adequate laboratory and learning resources and teachers’ teaching styles were reportedly the reasons behind the difficulty of these units. Therefore, the provision of continuous professional development training on advances in teaching and learning biochemistry to in-service teachers would be one of the strategies to enhance students’ understanding of these concepts. Keywords: Biochemistry, photosynthesis, enzymes, respiration, secondary school students.

The role of personal values in understanding pro-environmental attitudes and behaviors has received considerable attention from psychological researchers. However, little is known about the mutual interaction of personal values and the Theory of Ecological Attitudes (2-MEV) in explaining pro-environmental behaviors (PEBs). To explore the mediating factors with which pro-environmental behaviors are explained via environmental attitudes and personal values, this article reports the study findings from secondary school students. Specifically, the article indicates the extent to which a unified model of personal values and the Theory of Ecological Attitudes (2-MEV) explain self-reported PEBs. The cross-cultural validity of the 2-MEV for measuring environmental attitudes (EA) among the selected respondents is as well investigated. A cross-sectional survey of 408 secondary school students was used for data collection. As expected, principal component analysis with a varimax rotation confirmed the two-factor structure of the 2-MEV measuring EA with two uncorrelated factors of Preservation and Utilization. Interestingly, multiple regression analyses indicated that a combined model of personal values and the 2-MEV provides a more explained variance of self-reported PEBs compared to when any of the two predicators is used independently. Overall, altruistic value provides the largest predictive power over egoistic and biospheric values in mediating EA. In turn, the general model that includes personal values and the 2-MEV indicates that Preservation makes the largest and unique contribution in explaining recycling, biodiversity protection, environmental activism, and general PEBs. Conversely, the Utilization factor provides the largest negative explained variance for management of environmental pollution behavior. These findings remain unaltered even when the age of respondents and social desirability responding are statistically controlled. The implications regarding these study findings are discussed.

Literature affirms that teachers’ difficulties in mastering the subject content and its teaching can be responsible for students’ negative attitudes towards that subject. The present study sought to explore biology topics in the revised Rwandan curriculum which teachers have difficulties in teaching, the reasons for their difficulties, and ways to improve teaching and learning of such topics. Data were collected from a sample of 67 teachers who agreed to join the survey, and analysed both quantitatively and qualitatively. The results showed that 17 topics were considered difficult to teach and to learn. Molecular biology and biotechnology-related topics such as genetic engineering, gene technology, genetics, cell division, DNA replication, and protein synthesis were perceived as the most difficult to teach and learn. Teachers indicated a lack of content knowledge and visual teaching materials, inability to organise practical activities, overloaded curriculum, and the topics' abstractness to be among the reasons for the difficulty. Teachers suggested the use of virtual labs, 3D animations, provision of laboratory materials, reduction of the curriculum content, training and study visits as the practical options to alleviate the difficulties. Furthermore, the authors recommended different teachers’ professional development approaches and areas of focus for future research